Michael Barbella, Managing Editor10.01.20
Irie Felkner greeted this world a bit too early. Born at 27 weeks, the tiny pre-term infant weighed less than two pounds and spent her first post-womb days fighting for her life.
Irie was dealt the genetic equivalent of a 7-2 offset poker hand: The large blood vessel connecting her pulmonary artery and aorta failed to close, allowing blood from the two veins to mix. This biological blunder can cause the heart and lungs to work harder, and eventually the lungs to become congested.
The condition, known as patent ductus arteriosus (PDA), occurs in 5 to 10 percent of all children born with congenital heart disease. It is twice as likely to manifest itself in girls as in boys (Irie’s twin brother’s heart was normal), and is more common in babies born prematurely, according to industry data.
Fortunately for Irie, there was a technological fix for her anatomical anomaly—the Amplatzer Piccolo Occluder from Abbott Laboratories. Slightly larger than Roosevelt’s ear on the U.S. dime, the Occluder received U.S. Food and Drug Administration approval in January 2019.
Abbott’s Occluder, a minimally invasive self-expanding wire mesh, is inserted through a small leg incision and guided through blood vessels to the heart, where it is placed to seal the arterial opening. The product is designed to be inserted through the aortic or pulmonary artery, as well as to be retrieved and redeployed for optimal placement.
The Occluder device can be placed through either an anterograde (venous) or retrograde (arterial) approach. It has a 3mm-5mm diameter central waist and two retention discs with a 4mm-6.5mm diameter. The length between the two retention discs ranges from 2mm to 6mm.
The Occluder’s radiopaque marker bands at each end offer visibility during the fluoroscopy process. The device also features a hoop dispenser, a delivery wire, an occluder protector tube, and a micro screw attachment.
Within three days of receiving the Occluder, Irie was off the ventilator that had kept her alive. Today, she is a typical toddler, always on the move alongside her twin brother, and her heart disease is gone.
“You just have to live it to really fully appreciate what that device did for our daughter,” Irie’s father Matt said.
“What’s amazing is the device is so tiny—to go through the vein of a little baby that’s only one pound, 13 ounces,”Irie’s mother Crissa marveled in an Abbott-sponsored video. “I would definitely consider Abbott’s Piccolo device to be Irie’s lifesaver.”
Abbott cannot be given all the credit, though. Irie also owes her life to the technology that produces such tiny products, namely micromolding. The highly specialized manufacturing process can produce large volumes of minute, complex, and feature-rich components both efficiently and cost-effectively.
Micromolding has become an essential part of medtech product development in recent years as demand has grown for minimally invasive procedures and fixes to age-related conditions like glaucoma, cataracts, and macular degeneration. Manufacturers are constantly challenging micromolders to create ever-smaller parts with thinner walls and length-to diameter ratios that previously seemed theoretically impossible.
To gain insight into the micromolding process and the trends shaping this dynamic market, Medical Product Outsourcing spoke with various experts over the last several weeks. They included:
Donna Bibber, vice president of business development; and Wayne Shakal, vice president of operations at Isometric Micro Molding Inc., a vertically integrated micromolding company based in New Richmond, Wis.
Jared Cicio, production manager; John Clark, operations manager; Patrick Haney, R&D engineer; Gary Hulecki, executive vice president; Kyle Kolb, tooling supervisor; Lindsay Mann, sales/marketing director; and Sherry Simonson, account manager at MTD Micro Molding, a Charlton, Mass.-based micro medical manufacturer of ultra-precision molded components.
Scott Herbert, founder and president of Rapidwerks Inc., a Pleasanton, Calif.-based precision micromolder.
Aaron Johnson, vice president of marketing and customer strategy at Accumold, a high-tech manufacturer of precision micro, small, and lead frame injection-molded plastic components headquartered in Ankeny, Iowa.
Justin Strike, product manager at Trelleborg Healthcare & Medical, a global provider of engineered polymeric solutions for medical device, biotech, and pharmaceutical applications.
Raghu Vadlamudi, chief research and technology director at Donatelle, a New Brighton, Minn.-based firm providing medical device design, development, and contract manufacturing services. Its micromolding processes can achieve tight tolerances and create components that weigh less than 1 mg.
Michael Barbella: What are the latest innovations in micromolding technology?
John Clark: I wouldn’t say there is a lot of new innovation but improvements to existing technology have come a long way. This is in both tooling and molding.
Tooling: Cutters have become smaller and coatings on the cutting tools make the cutters last longer. Wire sizes on the wire EDM have become smaller and the cutting technology has allowed for finer finishes. Sinker EDM technology has allowed for smaller overcuts resulting in finer finishes.
Molding: Sodick has improved their hydraulic systems to deliver the polymer faster and with more repeatability but the base technology is the same.
Patrick Haney: Part features are getting smaller—wall thicknesses especially. Knowledge and equipment allows us to be successful in creating these part features. It comes down to strategy with building the tool and optimizing molding parameters. Knowledge from experience allows us to push the envelope even further than we could even just a couple years ago.
Materials knowledge at MTD has advanced quite a bit. We conduct in-depth studies for material behavior that are unique to micromolding and can identify and study various phenomena that we uncover. By weighing study results and relying on material engineering knowledge, applying to current and future projects. It is a combination of acquired knowledge and internally researching things that we don’t understand but want to.
Scott Herbert: [There are] many new concepts in the world of micromolding, specifically around rapid tooling. The key is fast-working prototypes that represent production-like products.
Aaron Johnson: At Accumold, our innovations are 100 percent driven by our customer’s needs. Lately our innovations have centered around high-velocity projects with high output, high-quality demand at high speed. Our innovation team is constantly developing new tools that enable tooling and production to solve some very complex customer demands.
Wayne Shakal: From a molding perspective, most of the new developments in micromolding have been incremental improvements in existing technologies. For example, micromolding machines continue to increase injection speeds and pressures. Close-looped response times are also getting faster and this is improving accuracy, which is critical for tight tolerance micro components. To date, we are not aware of any industry altering innovations, but we are aware of the need and currently have multiple R&D efforts in process.
Justin Strike: Silicone: Shot size control is critical for low viscosity LSR and is therefore a major focus with newer micromolding equipment. Without tight control over shot size, 5-10 percent of micro part cavity volume could easily be “leaked.”
Thermoplastics: In thermoplastic micromolding systems, the focus is on material quality. Molders are investing in custom injection units and bespoke material delivery systems that reduce material volume to minimize degradation prior to shot.
Raghu Vadlamudi: There is not much innovation beyond the “micromolding after screw over plunger technology” that a couple of injection molding machine manufacturers came up with a couple decades ago. Most advancements are happening in the part handling systems. One notable technology that entered the micromolding industry uses ultrasonic energy to melt plastic. This technology claims no material degradation during molding in addition to energy savings.
Barbella: What market forces are fueling the need for micromolding technology and services?
Donna Bibber: In the past few decades, traditional markets for micromolding have primarily been driven by minimally invasive surgery, which is still a main driver. In recent years, however, drug delivery devices such as aspirators, sub-Q injectors, dermal patches, implantable sensors, and wearable smart devices have driven new products requiring high volume micromolded components and automated assemblies.
Herbert: The medical field across the board is fueling smaller designs. The need to reduce size and increase capabilities is crucial.
Gary Hulecki: Insulin pumps for diabetes care have made great strides in miniaturization—they used to be the size of a fanny pack, then decreased in size to fit in a pocket, and now they can fit discretely on your body as a wearable and be the size of a quarter.
Johnson: It sounds cliché but the miniaturization trend in technology has not slowed—especially if you think of what it means to medical device. Miniaturization is a key driver for adding more features and/or allowing for further formfactor reductions. This often translates into better diagnostics, faster recoveries, or overall better patient care.
Lindsay Mann: The medical plastics industry is an ever-growing one. Minimally invasive surgeries are preferred for the benefit of quicker recovery times, fewer post-op complications, and better patient outcomes. These procedures require high-tech devices that can be comprised of tiny, complex micro plastic parts. That’s where we come in. Medical micro injection molding is our specialty.
Sherry Simonson: Bioabsorbable anchors/staples and drug delivery devices.
Strike: The miniaturization of medical devices is driving the need for micromolding of smaller components.
Vadlamudi: As the use of implantable pulse generators is expanded to other branches of medicine, such as neurology and ophthalmology to cardiology, the demand for smaller and smaller parts increased.
Medical devices in these fields are much smaller in comparison to the peripheral devices. Even in cardiology, transitioning to leadless pacemakers necessitated the design of micro parts, or in some cases parts with micro features.
Barbella: How is the need for smaller, more complex medical devices/components challenging micromolding suppliers and providers?
Jared Cicio: The need for smaller, more complex medical devices has made it challenging for micromolders for many reasons. The most difficult challenge we come across with smaller and more complex parts is that as the parts get smaller, the dimensional tolerances do too. These requirements paired with the need for very thin walls, which require faster injection speeds, create a near impossible situation that takes a very precisely made mold and a high level of processing knowledge to perfect.
Another major challenge with smaller, highly precise medical parts is handling. We can’t just drop a part out of the mold into a bucket. We design and build custom end of arm tools (EOAT) in house for our robotics that precisely extract the parts and runners from the molds and carefully place them into a collection system. We are extracting parts from molds with robotics and loading them into special trays, bags, or gel packs that will be shipped directly to customers. This requires lots of planning and forecasting to ensure proper automation is in place to keep up with customer demand.
One last thing I see as a challenge with more complex medical device designs is assembly. Most devices have multiple components that fit together to create the device. As devices get smaller and smaller, handling these components gets increasingly more difficult. Assembly steps need to be performed under a microscope using tweezers and with such tight tolerances, there is no room for error. This makes finding the right people that are qualified to do this work crucial, but challenging. It takes a lot of manual dexterity to be able to assemble a device under a microscope.
Haney: There are two categories—mindset and equipment capabilities.
Mindset: With parts and features continuing to get smaller, more complex, or both, the high demands of the medical device industry will not go away. There is more pressure for molders to provide evidence there is high confidence that a project can be completed successfully and on time. To continue to build that confidence, MTD needs to stay at the tip of the spear by ensuring we take steps now to anticipate the intricacies of how this technology will develop. Even though we don’t know what is coming next in the future, we have a department that is focused on R&D efforts to ensure we are ready.
Equipment capabilities: We have the ability to optimize our customers’ designs by making micro design changes to maximize the strength or optimize the functionality of a component. If we solved every problem we faced in a reactionary fashion, we would not be able to stay ahead of the curve. Because we solve problems theoretically, we have data to support the solution and we can use that data to extrapolate to solve problems in the future.
Herbert: The challenge is multi-faceted. Creating tool designs that will produce functional components is key, additionally without the need of expensive assembly procedures—i.e., welding or a glue process.
Johnson: Every time the need for smaller, more complex components pushes the boundaries, it challenges the supply chain. It becomes a way life. Micromolding suppliers should be ready to take on potential roadblocks and not dumb-down the part just to make it easier. Starting with the customer’s ideal is always goal number one.
Shakal: The development, FDA approval, and commercialization of micro-sized medical devices is more common than ever. This trend is naturally driving micromolders to continually increase the level of what can be manufactured. These new product needs are continuously requiring that we strive for and achieve new technology milestones. What was state-of-the-art yesterday might not be today. Feature sizes are getting so small that simply injecting faster or at higher temps isn’t enough. We are required to innovate and develop new processes and methods that are outside of what is considered standard injection molding. Along with the challenge of molding these micro components comes the challenge of being able to handle these components to prevent damage or not impart bioburden. This requires robotics and custom part retrieval systems for every micromolded component. Inspection is also an area that can be extremely challenging. Specialty metrology equipment such as micro CT scanners or laser microscopes are required, and often, customization of their normal intended use is required in order to develop a metrology process that is capable of meeting gauge R&R requirements on a tolerance that may be less than 5 microns. This expertise is accomplished through significant trial and error testing and is the enabler that allows us to succeed where others might fail. Lastly, as complicated and challenging as the micromolding might be, the assembly of these devices can be even more complex and difficult to scale to high-volume manufacturing. We are continuously having to push the limits of what is available with current vision and motion control and it is critical that we are able to design and build these systems in-house so that we control all aspects of the system. We have applications requiring 1 micron (.00004”) positional accuracy in the placement of components and this is a combination of tooling, vision, and motion precision. This can only work if you control all aspects of what is required.
Strike: For process validation, micromolding suppliers need machines that can process very small-scale components with tight control and quality inspection equipment with the same limits to measure and assess that control. Operators typically must manipulate and inspect finished parts, which at these smaller sizes, can be quite difficult. Therefore, molders are moving to more automated visual evaluation for post mold inspection and processing.
Vadlamudi: While there is quite a bit of information available for reference regarding macro parts, when it comes to micro parts, the micromolding suppliers are on their own to come up with solutions by trial and error. The need for innovation among service providers is very high. The stringent requirements in the medical device industry makes it more difficult when it comes to injection molding, as it is considered as a “special process” and has to be validated. Validating the injection molding process of a micro part is a Herculean task due to the tiny feature sizes. Establishing a measurement system is not easy when the parts weigh around a tenth of a milligram, and it’s difficult to fixture the part. There are no systems readily available to facilitate manufacturing of micro parts.
Barbella: What factors must be taken into consideration in designing tooling for micromolded parts?
Clark: The cutting tools available to create the geometry is a big factor. If the cutting tool you need doesn’t exist, splitting the core or cavity into smaller pieces gives the ability to cut the mold to be able to produce the most model like molded part.
Herbert: Key factors would consist of what is the end game, what are you trying to achieve, and in what specific material?
Johnson: There is no easy answer when answering, “What are the guidelines?” When it comes to micromolding, each part design brings a unique set of challenges to the equation. One of the primary considerations in what we call DfMM, Design for Micro Molding, is matching material selection and the part geometry. Understanding these relationships at the micro level takes experience over what a data sheet might say.
Kyle Kolb: Size and space constraints.
The need for perfect alignment between mold halves as well as interlocking molding components.
Ninety-five percent of mold base components need to be made custom due to size and the need for more precise alignment than off the shelf components can offer.
The need more precise travels and sequencing of mold actions. Sometimes having only .001” clearance between molded part and mold action during part ejection.
Heating and cooling become far more complicated, requiring custom components and need to be creative to get the inlets and outlets into the inserts that need it.
Gating locations often go against the old rule of thumb of “going thick to thin.”
Ejection: not only are pins and blades much smaller and are typically custom, but also size drives us to go with very non-traditional forms of ejection.
Mold inserts are very wire-EDM intensive in order to create tiny details, very often coming together like a puzzle. With the inserts being so small and packed so densely, retaining the inserts is often challenging and requires non-traditional methods to hold them in.
EOAT’s and other automation needs to be assessed as the tooling is being designed as traditional part picking methods don’t always work due to size and static.
Shakal: A tool designer must have a clear understanding of what is possible with micro-machining in order to properly design a mold that is manufacturable. For example, it is not uncommon for us to see part features that are only a few thousandths in size. The designer must know what machining method will be optimal to put the feature into the tool steel and whether or not there are limitations with cutter reach, cutter diameter, electrode overburn, accuracy requirements, etc. Often these limitations require separating this tool steel out from the rest of the cavity and manufacturing it as a standalone piece.
Knowing this is required adds complexity in fitting the componentry together without giving up positional accuracy of a micron. Also, due to the extreme injection speeds and extremely small fill volumes, the molds must be able to vent properly. This is important in any mold, but it is exceedingly more difficult to achieve in many micro applications. The difference from failure and success is once again at the micron level. A 1-2 micron difference in vent depth can be the difference between a part that will not fill and a part that has too much flash. It takes painstaking attention to detail, beginning at design and carried all the way through for these applications to be a success.
Strike: Micromolding with silicone requires tools that deliver a high degree of precision in shut-off surfaces. Thermoplastic tools need consistent cooling and precision. Regardless of the material, surface finishes are limited since conventional tool polishing could wipe out micro geometry. Finally, tools should exit the machining center or EDM bath ready for resin.
Vadlamudi: Tooling for micromolded parts needs to be precise. There is very little room for error or missing the target. The tooling needs to be designed to accommodate the entire manufacturing process from molding through packaging.
Barbella: Should micromolding tooling design be outsourced? Why or why not?
Clark: I think it depends on where you would outsource to. MTD has a very good tool design department and for that, I would never outsource any micro tool design work. However, if there was a need to outsource, then this type of work would only be outsourced to a shop that exclusively deals with micro. If outsourced to a macro mold designer, a lot of the design rules followed in macro are broken in micro and you may end up with design delays or design features that don’t work properly.
Haney: The number of shops that have the unique capability to design micromolds is limited. Sending micromold design work to mold designers who design macro tools primarily is problematic. Having tooling and processing constantly collaborate throughout the mold design process to get the design right the first time is imperative to a successful project. Micromolding projects without inhouse tooling support often result in longer lead times. Also, iteration processes take much longer when tooling is managed off site. This could work in the macro world, but not well in the micro world.
Herbert: Some tools can be outsourced and some should not be. It really comes down to the application and the material selected. Coupled with tolerances, this will dictate outsourcing or captive tools.
Johnson: In our opinion, no. If you are expecting microns in the outcome of the process in-house tooling is a must. Can you get good tooling on the outside? Absolutely. But we have found when working with a highly specialized process like micromolding, the pieces of the puzzle—tooling, processing, metrology, etc.—being vertically integrated leads to a faster and more robust process. Tooling is such a critical part of the success at this level it would be hard not to have full control.
Kolb: To be successful, there needs to be an intimate knowledge of the full manufacturing picture—toolmakers’ abilities, machining capabilities and capacities, as well as knowledge of our injection molding machines and automation capabilities. The need to control IP, since the mold designs contain both proprietary design information as well as insight into manufacturing processes. In-house design is required to keep communication flowing between all departments as tool makers, process engineers as well as others all have upfront input that needs to be relayed quickly and concisely during the design phase. Going back and forth with a design house creates time delays.
Shakal: From experience, we feel very strongly that to provide successful results for a true micro application that is not only micro in size but also has micron level tolerances requires the supplier to be vertically integrated. Tooling is one of the key enablers to the success of a micro program and we don’t believe that we could be timely and effective with outsourced tooling. There is simply too much interaction required between the tooling and development molding teams to do this efficiently with outside resources. It is also important from our perspective that this vertical integration not only exists between tooling and molding but also part handling automation, all metrology, and automated component assembly. The tolerance stack-ups are often so tight that we must control every aspect of manufacturing. It takes considerable resources and time to build up this diverse skill set but it is critical to our customer’s success that we be able to provide this level of service.
Strike: Micromolding challenges are universal. Device manufacturers with one or two micro forms to mold would benefit from outsourcing those programs to a molder that has implemented universal solutions to avoid excess capital and personnel expense. This is true for the tooling, but perhaps more importantly for the processing of those tools. Tool design for micromolding should take the processing equipment into consideration. Therefore, when outsourcing tool design, the molder should make the tooling designer or manufacturer aware of the processing equipment that will be used.
The tool design and/or build strategy will utilize the machining equipment to minimize fit error. It begins with the equipment being used to manufacture the tooling and ends with the injection molding machine being used to process the tool. Because of the unique challenges facing micromolded components, we found it beneficial to accomplish the tool design, build, and processing under one roof. This will help reduce the time to a successful molding.
Vadlamudi: This would depend on how the micromolding services are provided. It is advantageous to have mold design and building capabilities in-house for a micromolder. Understanding the injection molding process and maintaining the tooling in-house plays a critical role in meeting the customer’s expectations. Outsourcing the design of tooling might extend the project time lines and result in miscommunication of requirements.
Irie was dealt the genetic equivalent of a 7-2 offset poker hand: The large blood vessel connecting her pulmonary artery and aorta failed to close, allowing blood from the two veins to mix. This biological blunder can cause the heart and lungs to work harder, and eventually the lungs to become congested.
The condition, known as patent ductus arteriosus (PDA), occurs in 5 to 10 percent of all children born with congenital heart disease. It is twice as likely to manifest itself in girls as in boys (Irie’s twin brother’s heart was normal), and is more common in babies born prematurely, according to industry data.
Fortunately for Irie, there was a technological fix for her anatomical anomaly—the Amplatzer Piccolo Occluder from Abbott Laboratories. Slightly larger than Roosevelt’s ear on the U.S. dime, the Occluder received U.S. Food and Drug Administration approval in January 2019.
Abbott’s Occluder, a minimally invasive self-expanding wire mesh, is inserted through a small leg incision and guided through blood vessels to the heart, where it is placed to seal the arterial opening. The product is designed to be inserted through the aortic or pulmonary artery, as well as to be retrieved and redeployed for optimal placement.
The Occluder device can be placed through either an anterograde (venous) or retrograde (arterial) approach. It has a 3mm-5mm diameter central waist and two retention discs with a 4mm-6.5mm diameter. The length between the two retention discs ranges from 2mm to 6mm.
The Occluder’s radiopaque marker bands at each end offer visibility during the fluoroscopy process. The device also features a hoop dispenser, a delivery wire, an occluder protector tube, and a micro screw attachment.
Within three days of receiving the Occluder, Irie was off the ventilator that had kept her alive. Today, she is a typical toddler, always on the move alongside her twin brother, and her heart disease is gone.
“You just have to live it to really fully appreciate what that device did for our daughter,” Irie’s father Matt said.
“What’s amazing is the device is so tiny—to go through the vein of a little baby that’s only one pound, 13 ounces,”Irie’s mother Crissa marveled in an Abbott-sponsored video. “I would definitely consider Abbott’s Piccolo device to be Irie’s lifesaver.”
Abbott cannot be given all the credit, though. Irie also owes her life to the technology that produces such tiny products, namely micromolding. The highly specialized manufacturing process can produce large volumes of minute, complex, and feature-rich components both efficiently and cost-effectively.
Micromolding has become an essential part of medtech product development in recent years as demand has grown for minimally invasive procedures and fixes to age-related conditions like glaucoma, cataracts, and macular degeneration. Manufacturers are constantly challenging micromolders to create ever-smaller parts with thinner walls and length-to diameter ratios that previously seemed theoretically impossible.
To gain insight into the micromolding process and the trends shaping this dynamic market, Medical Product Outsourcing spoke with various experts over the last several weeks. They included:
Donna Bibber, vice president of business development; and Wayne Shakal, vice president of operations at Isometric Micro Molding Inc., a vertically integrated micromolding company based in New Richmond, Wis.
Jared Cicio, production manager; John Clark, operations manager; Patrick Haney, R&D engineer; Gary Hulecki, executive vice president; Kyle Kolb, tooling supervisor; Lindsay Mann, sales/marketing director; and Sherry Simonson, account manager at MTD Micro Molding, a Charlton, Mass.-based micro medical manufacturer of ultra-precision molded components.
Scott Herbert, founder and president of Rapidwerks Inc., a Pleasanton, Calif.-based precision micromolder.
Aaron Johnson, vice president of marketing and customer strategy at Accumold, a high-tech manufacturer of precision micro, small, and lead frame injection-molded plastic components headquartered in Ankeny, Iowa.
Justin Strike, product manager at Trelleborg Healthcare & Medical, a global provider of engineered polymeric solutions for medical device, biotech, and pharmaceutical applications.
Raghu Vadlamudi, chief research and technology director at Donatelle, a New Brighton, Minn.-based firm providing medical device design, development, and contract manufacturing services. Its micromolding processes can achieve tight tolerances and create components that weigh less than 1 mg.
Michael Barbella: What are the latest innovations in micromolding technology?
John Clark: I wouldn’t say there is a lot of new innovation but improvements to existing technology have come a long way. This is in both tooling and molding.
Tooling: Cutters have become smaller and coatings on the cutting tools make the cutters last longer. Wire sizes on the wire EDM have become smaller and the cutting technology has allowed for finer finishes. Sinker EDM technology has allowed for smaller overcuts resulting in finer finishes.
Molding: Sodick has improved their hydraulic systems to deliver the polymer faster and with more repeatability but the base technology is the same.
Patrick Haney: Part features are getting smaller—wall thicknesses especially. Knowledge and equipment allows us to be successful in creating these part features. It comes down to strategy with building the tool and optimizing molding parameters. Knowledge from experience allows us to push the envelope even further than we could even just a couple years ago.
Materials knowledge at MTD has advanced quite a bit. We conduct in-depth studies for material behavior that are unique to micromolding and can identify and study various phenomena that we uncover. By weighing study results and relying on material engineering knowledge, applying to current and future projects. It is a combination of acquired knowledge and internally researching things that we don’t understand but want to.
Scott Herbert: [There are] many new concepts in the world of micromolding, specifically around rapid tooling. The key is fast-working prototypes that represent production-like products.
Aaron Johnson: At Accumold, our innovations are 100 percent driven by our customer’s needs. Lately our innovations have centered around high-velocity projects with high output, high-quality demand at high speed. Our innovation team is constantly developing new tools that enable tooling and production to solve some very complex customer demands.
Wayne Shakal: From a molding perspective, most of the new developments in micromolding have been incremental improvements in existing technologies. For example, micromolding machines continue to increase injection speeds and pressures. Close-looped response times are also getting faster and this is improving accuracy, which is critical for tight tolerance micro components. To date, we are not aware of any industry altering innovations, but we are aware of the need and currently have multiple R&D efforts in process.
Justin Strike: Silicone: Shot size control is critical for low viscosity LSR and is therefore a major focus with newer micromolding equipment. Without tight control over shot size, 5-10 percent of micro part cavity volume could easily be “leaked.”
Thermoplastics: In thermoplastic micromolding systems, the focus is on material quality. Molders are investing in custom injection units and bespoke material delivery systems that reduce material volume to minimize degradation prior to shot.
Raghu Vadlamudi: There is not much innovation beyond the “micromolding after screw over plunger technology” that a couple of injection molding machine manufacturers came up with a couple decades ago. Most advancements are happening in the part handling systems. One notable technology that entered the micromolding industry uses ultrasonic energy to melt plastic. This technology claims no material degradation during molding in addition to energy savings.
Barbella: What market forces are fueling the need for micromolding technology and services?
Donna Bibber: In the past few decades, traditional markets for micromolding have primarily been driven by minimally invasive surgery, which is still a main driver. In recent years, however, drug delivery devices such as aspirators, sub-Q injectors, dermal patches, implantable sensors, and wearable smart devices have driven new products requiring high volume micromolded components and automated assemblies.
Herbert: The medical field across the board is fueling smaller designs. The need to reduce size and increase capabilities is crucial.
Gary Hulecki: Insulin pumps for diabetes care have made great strides in miniaturization—they used to be the size of a fanny pack, then decreased in size to fit in a pocket, and now they can fit discretely on your body as a wearable and be the size of a quarter.
Johnson: It sounds cliché but the miniaturization trend in technology has not slowed—especially if you think of what it means to medical device. Miniaturization is a key driver for adding more features and/or allowing for further formfactor reductions. This often translates into better diagnostics, faster recoveries, or overall better patient care.
Lindsay Mann: The medical plastics industry is an ever-growing one. Minimally invasive surgeries are preferred for the benefit of quicker recovery times, fewer post-op complications, and better patient outcomes. These procedures require high-tech devices that can be comprised of tiny, complex micro plastic parts. That’s where we come in. Medical micro injection molding is our specialty.
Sherry Simonson: Bioabsorbable anchors/staples and drug delivery devices.
Strike: The miniaturization of medical devices is driving the need for micromolding of smaller components.
Vadlamudi: As the use of implantable pulse generators is expanded to other branches of medicine, such as neurology and ophthalmology to cardiology, the demand for smaller and smaller parts increased.
Medical devices in these fields are much smaller in comparison to the peripheral devices. Even in cardiology, transitioning to leadless pacemakers necessitated the design of micro parts, or in some cases parts with micro features.
Barbella: How is the need for smaller, more complex medical devices/components challenging micromolding suppliers and providers?
Jared Cicio: The need for smaller, more complex medical devices has made it challenging for micromolders for many reasons. The most difficult challenge we come across with smaller and more complex parts is that as the parts get smaller, the dimensional tolerances do too. These requirements paired with the need for very thin walls, which require faster injection speeds, create a near impossible situation that takes a very precisely made mold and a high level of processing knowledge to perfect.
Another major challenge with smaller, highly precise medical parts is handling. We can’t just drop a part out of the mold into a bucket. We design and build custom end of arm tools (EOAT) in house for our robotics that precisely extract the parts and runners from the molds and carefully place them into a collection system. We are extracting parts from molds with robotics and loading them into special trays, bags, or gel packs that will be shipped directly to customers. This requires lots of planning and forecasting to ensure proper automation is in place to keep up with customer demand.
One last thing I see as a challenge with more complex medical device designs is assembly. Most devices have multiple components that fit together to create the device. As devices get smaller and smaller, handling these components gets increasingly more difficult. Assembly steps need to be performed under a microscope using tweezers and with such tight tolerances, there is no room for error. This makes finding the right people that are qualified to do this work crucial, but challenging. It takes a lot of manual dexterity to be able to assemble a device under a microscope.
Haney: There are two categories—mindset and equipment capabilities.
Mindset: With parts and features continuing to get smaller, more complex, or both, the high demands of the medical device industry will not go away. There is more pressure for molders to provide evidence there is high confidence that a project can be completed successfully and on time. To continue to build that confidence, MTD needs to stay at the tip of the spear by ensuring we take steps now to anticipate the intricacies of how this technology will develop. Even though we don’t know what is coming next in the future, we have a department that is focused on R&D efforts to ensure we are ready.
Equipment capabilities: We have the ability to optimize our customers’ designs by making micro design changes to maximize the strength or optimize the functionality of a component. If we solved every problem we faced in a reactionary fashion, we would not be able to stay ahead of the curve. Because we solve problems theoretically, we have data to support the solution and we can use that data to extrapolate to solve problems in the future.
Herbert: The challenge is multi-faceted. Creating tool designs that will produce functional components is key, additionally without the need of expensive assembly procedures—i.e., welding or a glue process.
Johnson: Every time the need for smaller, more complex components pushes the boundaries, it challenges the supply chain. It becomes a way life. Micromolding suppliers should be ready to take on potential roadblocks and not dumb-down the part just to make it easier. Starting with the customer’s ideal is always goal number one.
Shakal: The development, FDA approval, and commercialization of micro-sized medical devices is more common than ever. This trend is naturally driving micromolders to continually increase the level of what can be manufactured. These new product needs are continuously requiring that we strive for and achieve new technology milestones. What was state-of-the-art yesterday might not be today. Feature sizes are getting so small that simply injecting faster or at higher temps isn’t enough. We are required to innovate and develop new processes and methods that are outside of what is considered standard injection molding. Along with the challenge of molding these micro components comes the challenge of being able to handle these components to prevent damage or not impart bioburden. This requires robotics and custom part retrieval systems for every micromolded component. Inspection is also an area that can be extremely challenging. Specialty metrology equipment such as micro CT scanners or laser microscopes are required, and often, customization of their normal intended use is required in order to develop a metrology process that is capable of meeting gauge R&R requirements on a tolerance that may be less than 5 microns. This expertise is accomplished through significant trial and error testing and is the enabler that allows us to succeed where others might fail. Lastly, as complicated and challenging as the micromolding might be, the assembly of these devices can be even more complex and difficult to scale to high-volume manufacturing. We are continuously having to push the limits of what is available with current vision and motion control and it is critical that we are able to design and build these systems in-house so that we control all aspects of the system. We have applications requiring 1 micron (.00004”) positional accuracy in the placement of components and this is a combination of tooling, vision, and motion precision. This can only work if you control all aspects of what is required.
Strike: For process validation, micromolding suppliers need machines that can process very small-scale components with tight control and quality inspection equipment with the same limits to measure and assess that control. Operators typically must manipulate and inspect finished parts, which at these smaller sizes, can be quite difficult. Therefore, molders are moving to more automated visual evaluation for post mold inspection and processing.
Vadlamudi: While there is quite a bit of information available for reference regarding macro parts, when it comes to micro parts, the micromolding suppliers are on their own to come up with solutions by trial and error. The need for innovation among service providers is very high. The stringent requirements in the medical device industry makes it more difficult when it comes to injection molding, as it is considered as a “special process” and has to be validated. Validating the injection molding process of a micro part is a Herculean task due to the tiny feature sizes. Establishing a measurement system is not easy when the parts weigh around a tenth of a milligram, and it’s difficult to fixture the part. There are no systems readily available to facilitate manufacturing of micro parts.
Barbella: What factors must be taken into consideration in designing tooling for micromolded parts?
Clark: The cutting tools available to create the geometry is a big factor. If the cutting tool you need doesn’t exist, splitting the core or cavity into smaller pieces gives the ability to cut the mold to be able to produce the most model like molded part.
Herbert: Key factors would consist of what is the end game, what are you trying to achieve, and in what specific material?
Johnson: There is no easy answer when answering, “What are the guidelines?” When it comes to micromolding, each part design brings a unique set of challenges to the equation. One of the primary considerations in what we call DfMM, Design for Micro Molding, is matching material selection and the part geometry. Understanding these relationships at the micro level takes experience over what a data sheet might say.
Kyle Kolb: Size and space constraints.
The need for perfect alignment between mold halves as well as interlocking molding components.
Ninety-five percent of mold base components need to be made custom due to size and the need for more precise alignment than off the shelf components can offer.
The need more precise travels and sequencing of mold actions. Sometimes having only .001” clearance between molded part and mold action during part ejection.
Heating and cooling become far more complicated, requiring custom components and need to be creative to get the inlets and outlets into the inserts that need it.
Gating locations often go against the old rule of thumb of “going thick to thin.”
Ejection: not only are pins and blades much smaller and are typically custom, but also size drives us to go with very non-traditional forms of ejection.
Mold inserts are very wire-EDM intensive in order to create tiny details, very often coming together like a puzzle. With the inserts being so small and packed so densely, retaining the inserts is often challenging and requires non-traditional methods to hold them in.
EOAT’s and other automation needs to be assessed as the tooling is being designed as traditional part picking methods don’t always work due to size and static.
Shakal: A tool designer must have a clear understanding of what is possible with micro-machining in order to properly design a mold that is manufacturable. For example, it is not uncommon for us to see part features that are only a few thousandths in size. The designer must know what machining method will be optimal to put the feature into the tool steel and whether or not there are limitations with cutter reach, cutter diameter, electrode overburn, accuracy requirements, etc. Often these limitations require separating this tool steel out from the rest of the cavity and manufacturing it as a standalone piece.
Knowing this is required adds complexity in fitting the componentry together without giving up positional accuracy of a micron. Also, due to the extreme injection speeds and extremely small fill volumes, the molds must be able to vent properly. This is important in any mold, but it is exceedingly more difficult to achieve in many micro applications. The difference from failure and success is once again at the micron level. A 1-2 micron difference in vent depth can be the difference between a part that will not fill and a part that has too much flash. It takes painstaking attention to detail, beginning at design and carried all the way through for these applications to be a success.
Strike: Micromolding with silicone requires tools that deliver a high degree of precision in shut-off surfaces. Thermoplastic tools need consistent cooling and precision. Regardless of the material, surface finishes are limited since conventional tool polishing could wipe out micro geometry. Finally, tools should exit the machining center or EDM bath ready for resin.
Vadlamudi: Tooling for micromolded parts needs to be precise. There is very little room for error or missing the target. The tooling needs to be designed to accommodate the entire manufacturing process from molding through packaging.
Barbella: Should micromolding tooling design be outsourced? Why or why not?
Clark: I think it depends on where you would outsource to. MTD has a very good tool design department and for that, I would never outsource any micro tool design work. However, if there was a need to outsource, then this type of work would only be outsourced to a shop that exclusively deals with micro. If outsourced to a macro mold designer, a lot of the design rules followed in macro are broken in micro and you may end up with design delays or design features that don’t work properly.
Haney: The number of shops that have the unique capability to design micromolds is limited. Sending micromold design work to mold designers who design macro tools primarily is problematic. Having tooling and processing constantly collaborate throughout the mold design process to get the design right the first time is imperative to a successful project. Micromolding projects without inhouse tooling support often result in longer lead times. Also, iteration processes take much longer when tooling is managed off site. This could work in the macro world, but not well in the micro world.
Herbert: Some tools can be outsourced and some should not be. It really comes down to the application and the material selected. Coupled with tolerances, this will dictate outsourcing or captive tools.
Johnson: In our opinion, no. If you are expecting microns in the outcome of the process in-house tooling is a must. Can you get good tooling on the outside? Absolutely. But we have found when working with a highly specialized process like micromolding, the pieces of the puzzle—tooling, processing, metrology, etc.—being vertically integrated leads to a faster and more robust process. Tooling is such a critical part of the success at this level it would be hard not to have full control.
Kolb: To be successful, there needs to be an intimate knowledge of the full manufacturing picture—toolmakers’ abilities, machining capabilities and capacities, as well as knowledge of our injection molding machines and automation capabilities. The need to control IP, since the mold designs contain both proprietary design information as well as insight into manufacturing processes. In-house design is required to keep communication flowing between all departments as tool makers, process engineers as well as others all have upfront input that needs to be relayed quickly and concisely during the design phase. Going back and forth with a design house creates time delays.
Shakal: From experience, we feel very strongly that to provide successful results for a true micro application that is not only micro in size but also has micron level tolerances requires the supplier to be vertically integrated. Tooling is one of the key enablers to the success of a micro program and we don’t believe that we could be timely and effective with outsourced tooling. There is simply too much interaction required between the tooling and development molding teams to do this efficiently with outside resources. It is also important from our perspective that this vertical integration not only exists between tooling and molding but also part handling automation, all metrology, and automated component assembly. The tolerance stack-ups are often so tight that we must control every aspect of manufacturing. It takes considerable resources and time to build up this diverse skill set but it is critical to our customer’s success that we be able to provide this level of service.
Strike: Micromolding challenges are universal. Device manufacturers with one or two micro forms to mold would benefit from outsourcing those programs to a molder that has implemented universal solutions to avoid excess capital and personnel expense. This is true for the tooling, but perhaps more importantly for the processing of those tools. Tool design for micromolding should take the processing equipment into consideration. Therefore, when outsourcing tool design, the molder should make the tooling designer or manufacturer aware of the processing equipment that will be used.
The tool design and/or build strategy will utilize the machining equipment to minimize fit error. It begins with the equipment being used to manufacture the tooling and ends with the injection molding machine being used to process the tool. Because of the unique challenges facing micromolded components, we found it beneficial to accomplish the tool design, build, and processing under one roof. This will help reduce the time to a successful molding.
Vadlamudi: This would depend on how the micromolding services are provided. It is advantageous to have mold design and building capabilities in-house for a micromolder. Understanding the injection molding process and maintaining the tooling in-house plays a critical role in meeting the customer’s expectations. Outsourcing the design of tooling might extend the project time lines and result in miscommunication of requirements.
