Precision Machining & Prototypes Ultra High-Performance Polymers

Decades of processing and precision CNC machining high-performance polymer stock shapes assure optimal properties and quality in finished parts.

Drake’s specific area of precision-machining expertise is in ultra high-performance polymers. This includes Drake-produced shapes of Torlon PAI, Victrex and KetaSpire KT-820 and XT-920 PEEK, Ultem PEI, AvaSpire PAEKRyton PPS and Drake PAI as well as Vespel, Meldin (PI), Celazole PBI and other high end polymer materials and exotic composites.  In addition Drake provides several specialized post-production services including injection molded parts that are then precision machined to meet more demanding application specifications and tolerances.

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Precision CNC Machining

Ultra high-performance Torlon PAI, PEEK, Ryton PPS, Drake PAI, Ultem PEI and AvaSpire PAEK are specified for critical components that must perform long term in severe application environments. However, achieving their optimum performance in finished parts and ensuring they perform consistently lot-to-lot depends heavily on how these materials are processed and machined.

With decades of processing and application experience, Drake’s intimate knowledge of these polymers puts us in a unique position to preserve and deliver the properties you specify and expect in your finished parts. Our ongoing investments in state-of-the-art 5-axis CNC machining equipment is part of that commitment.

Customers routinely rely on Drake’s depth of experience not only to recommend materials and grades, but also to define the best manufacturing methods, part orientation within a shape for machining, tolerances, surface finishes, and annealing and post cure operations, all of which can affect performance in use.  In addition, our expertise in achieving finishes, feature geometry, primers, coatings and part marking can optimize your machined parts’ appearance.

Our focus on quality is reflected throughout our operations and by our skilled operators’ pride in their work and workplace. Customers who visit often comment that our machine shop is the cleanest they have ever seen.

Prototyping

Many new parts require samples for fit and finish or testing and evaluation. Drake is well equipped to offer machined prototypes quickly and economically in advance of full-scale production.

Machining Case Studies

Consider these examples of how Drake puts its team and its technology to work to help customers solve problems and improve part performance and reliability:

Manufacturing Methods: Resolving Snowmobile CVT Clutch Roller Failures 

When a major OEM experienced failures with rollers made from Vespel SP-1, , they turned to Drake for solutions. We provided machined prototypes and initial production from Torlon 4203L rod. For production cost reasons the OEM built a 4-cavity mold for Torlon with their legacy injection molding partner rather than continue with machining. Part failures continued, however, and the customer returned to Drake.

Drake’s engineers pointed out the critical factors behind the failures: The heavy sections of the part had a differential in cooling rate which negatively affected internal stresses, and the lower molecular weight of injection molding grade Torlon 4203L resin has inherently lower impact resistance than the extrusion grade. As a result, the heavy-walled molded parts could not withstand the high impacts that presented no problem for parts machined from tough and resilient extruded stock shapes.

Drake extrudes products from high molecular weight resins which have higher toughness, and we slow cool finished shapes to minimize residual stresses. Both factors helped resolve the performance issue. Drake then went to work on the cost difference first by making a custom diameter rod that matched the part OD. The machined part’s material efficiency then matched the injection molded version inclusive of the runner. Then Drake employed high speed machining that and approximated the injection molding production rate.

Result: Precision machined parts that perform, with a net cost equal to the injection molded version that would not work in this application.

Part Orientation: High Loads on Aerospace Sector Gear

Based on physical properties data, a major aerospace company chose 30% carbon fiber reinforced Torlon 7130 for a highly loaded sector gear. However, they were not aware that the resin supplier’s data sheet reported properties measured in the direction of fiber flow and reported values are not isotropic.  Mold flow and FEA analysis of an injection molded part demonstrated the gear teeth would be considerably weaker than was assumed by using the strength values published in Solvay’s Data Sheet, regardless of gating.

A part drawing was created which specified the parts’ precise orientation within our extruded Torlon 7130 plate to ensure consistent placement and performance.

Result: Test results consistently well above design minimums and multiple,  flawless launches and deployments.

Tolerances: Frac Ball Performance & Reliability

A major supplier of fracking tools and services came to Drake for a high strength, high temperature resistant drillable frac ball for a 60-zone system requiring less than 2% interference with the ball seats. Their drawings specified +/- .005”/ 1.27mm tolerances and sphericity. Drake FEA analysis backed up by testing determined that the tolerances as defined were much too wide for the parts to work reliably.

The strength needed for the frac balls required high fiber loading, which can negatively affect ductility and impact performance unless the parts have an optimal design for the severe application conditions. If they were slightly out of round, the high fiber content balls would shear fail under the extreme loads of hydraulic fracking.

Drake recommended and still produces high strength frac balls at less than 1/3 of the tolerance spec the customer originally requested,  in sizes up to 4.0”/ 100 mm. Their high fiber content coupled with this much tighter tolerance control has ensured tens of thousands of successful deployments and zero failures.

Result: Flawless, reliable system performance. And the principal engineer mused, “in 30 years, I have never had a machined part suppler recommend tolerances 3 times tighter than we asked for.”

Machined Finishes: Impact on properties and part performance.

An aerospace company purchased Drake extruded KetaSpire KT-820 CF30 30% CF reinforced PEEK plate to characterize the material and develop a material specification. They sent the plate to a major testing lab for sample prep and to measure physical properties. The property results were disturbing: very wide scatter, some respectable, but many very low in both strength and elongation.

Drake requested the samples for analysis and discovered poor quality machining. We then provided machined specimens from the same lot of material with our typical 32 RMS/ 0.8 Ra or better finish for specimens. The resulting properties were excellent and highly consistent, demonstrating the critical importance of good surface finishes to the performance of high strength fiber-reinforced polymers with low elongations like the carbon fiber reinforced PEEK used for this application. Other frequently specified reinforced materials where surface finish plays a beneficial role include KetaSpire KT-820 GF30 and 450GL30 PEEK with glass-fibers, Victrex 450CA30 and KetaSpire KT820-CF30 carbon fiber reinforced grades, 40% glass reinforced Ryton R-4 PPS, and Torlon PAI 5030, 5060 and 7130 grades.   

Result: Based on our standards, the customer updated their specifications for machined part finishes to realize these major consistency and performance benefits.

The Long View: Taking the Initiative on Cost-Effective Solutions

Drake routinely develops machined prototypes from our vast range of stock shapes for application testing and validation before parts go into full production. Once performance has been proven, we get busy with the customer to  ‘lean out’ the economics by defining the optimum production method based on the part attributes and quantity required. Options include machining the part from the most efficient stock shape size, injection molding a near-net shape then finish-machining to part dimensions or going directly to injection molding with the option to finish machine certain features.

 For example, these high voltage connectors were originally 5-axis machined from glass-reinforced KetaSpire KT820 GF30 PEEK Rod. The OEM refined both the material selected and the design three times to optimize electrical performance and assembly fit. Prototype parts machined by Drake from the third iteration were field tested and validated. Based on the cost of machining rod into parts with exceptionally tight tolerances,  the quantity of several hundred per year and the anticipated long production life of the product, the decision was then taken to invest in tooling and transition the parts from machining to injection molding.

Customers have come to appreciate Drake’s initiative in recommending more cost-effective parts production opportunities when their machined unit quantities reach appropriate levels. Our versatile operations provide the full gamut of polymer parts manufacturing capabilities for efficient solutions that keep pace with growing production volumes:

  • Our unmatched array of stock shape sizes and configurations serves most applications efficiently with minimal material loss. But when needed, our versatile shapes extrusion technology in ultra high-performance polymers opens the opportunity to develop custom sizes that more closely approximate final part dimensions.
  • Customers also work with our injection molding team to design and produce near-net part configurations that are then precision-machined to finished tolerances.
  • When production volumes justify the tooling investment, Drake’s molding expertise in ultra high-performance plastics allows customers to transition from precision machined to precision injection molded parts in the same “as-specified” polymer material.

Customer Support, Growth and Development

Customer Support – Machine Shops Worldwide

We are proud of our working relationship as a stock shapes supplier to machining customers worldwide that are dedicated to producing parts from our ultra high-performance polymer stock shapes. We support these world class companies with machining guidelines, precision blanks and centerless ground rod and technical information related to the products we supply them. For a referral to an exceptional plastic machine shop in your area or a shop with specific capabilities, ASK DRAKE.

Equipment: Staying Ahead of the Curve

Investments in equipment ensure that we maintain leading edge technology in production and quality and at the same time uphold our customer-centric high bar on service and delivery.  To support our high standards for quality, consistency and productivity, we employ the most current machine tools including 5-axis CNC milling, Live Tool equipped lathes, and exclusively use PDC tooling to deliver the very best surface finish and tightest tolerances possible.

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Post-Machining Services

Drake also provides extensive post-machining services to support customers whose parts must meet specialized or complex requirements:

  • Lot and batch traceability standard on every part.
  • Selectively orienting parts produced from reinforced polymers where fiber orientation is critical to performance.
  • Post-curing Torlon PAI and Drake PAI parts to achieve maximum wear and chemical performance.
  • Annealing to enhance dimensional stability of parts through fabrication and in use.
  • Specialized finishing including coating and laser engraving.
  • CT Scanning: Computed Tomography inspection
  • CMM: Coordinate Measuring Machine part inspection.
  • Mechanical testing for physical properties, Tensile, Elongation, Flexural and Compression on calibrated equipment (Instron 3369)
  • Material and process certifications

Drake as a Custom Material Development Partner

Companies often work with us on a confidential basis as a development partner to produce prototypes and test parts from their own proprietary material compositions. Our feedback on processing and machining characteristics helps fine-tune formulations to improve machinability and enhance finished part performance. We also provide support with parts production to help these companies launch new products and systems that incorporate critical components made from their exotic materials.