Case Studies

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Multi-Eccentric Shaft:
Precision Grinding for Space

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Problem:

A customer required a multi-eccentric shaft for a space-related compressor prototype, designed to support closed-loop water generation systems used in space environments.

The component featured five precision-ground diameters on separate centerlines, each requiring exact angular alignment and timing relative to the others. Tight tolerances—including .00012″ runout and true position—created a highly constrained process window where geometry, tolerance stack-up, and sequence were fully interdependent.

Traditional manufacturing approaches were insufficient due to:

  • Stacked tolerances across multiple eccentric features
  • Limited ability to correct errors during final grinding passes
  • Lack of inspection systems capable of verifying all features simultaneously

This created significant risk in both precision grinding execution and dimensional validation, where failure in one feature could compromise the entire part.

Resolution

KMM developed a three-stage grinding methodology (rough, semi-finish, final) to gradually bring each feature into specification. In-process measurement between passes ensured stability before progressing, reducing the risk of over-removal or geometric drift.

To overcome inspection limitations, KMM engineered a custom hybrid measurement system:

  • Multiple high-resolution indicators tracked all eccentric features simultaneously
  • Rotational validation confirmed that all features returned to zero at the same point
  • Supporting CMM and precision measurement tools verified individual dimensions

This approach enabled full-system validation of complex eccentric geometry, ensuring both dimensional accuracy and correct feature timing.

Material:

440C Stainless Steel Multi-Eccentric Shaft

Capabilities

  • Precision OD grinding of multi-eccentric shafts
  • Multi-axis geometry with independent centerlines
  • Tight tolerance grinding under stacked conditions
  • True position: .00012″
  • Runout: .00012″
  • Cylindricity: .0002″
  • Total diameter tolerance: .0003″
  • Surface finish: 8 RMS
  • Advanced process development for high-risk geometries
  • Custom inspection and validation methods for complex parts

Neurovascular Wire

Discover Our Neurovascular Manufacturing Solutions

Problem

Material: Nitinol Wire

A contract manufacturer had significant supply and quality issues with a challenging Nitinol wire. The incumbent supplier had over 1 year to ramp their capacity to production levels, but continually struggled to support the program. The issues with quality and production not only jeopardized the contract manufacturers standing with the end user, but also created a potential line-down scenario for the end user.

Resolution

Given only two months to develop a process and validate, KMM was able to get up to speed to keep production flowing. Solutions were engineered for extremely challenging part features that caused continual quality issues. Production flow was maintained, the line-down situation was averted, and the contract manufacturer’s preferred standing with the end user was maintained.

Capabilities

  • 1.5 meter grind length – overall part length was 2 meters
  • Multiple diameter sizes – down to .003″
  • Tolerances: +/-.0002″
  • End face of to be perpendicular .0001″
  • 8 Ra surface finish max

Mandrel Manufacturing for a Large OEM

Problem

Material: Stainless Steel

A large OEM of catheters and dilators was struggling with quality of the manufacturing aides – mandrels – used to make their products. Mandrel quality had dropped to a point that the OEM had put in place costly systems to reject sub-standard mandrels that had been allowed to enter into the manufacturing system. Cost and product quality had suffered due to inconsistent mandrel quality.

Resolution

KMM evaluated the requirements necessary to produce the mandrels consistently. 10,000 mandrels were produced on an initial run without a single rejection. Product quality improved and the need for the expensive mandrel sorting system was eliminated. From this initial project, KMM has replaced the incumbent supplier with the OEM as a primary tooling supplier.

Capabilities

  • Multiple diameters and a 17” part length made this project somewhat complex
  • Diameter tolerances to +/-.0002”
  • Tapered transitions between diameters
  • 8 Ra surface finish max

KMM's Ultra-Precision Machining Accelerates Medical Innovation

A high-tech healthcare equipment company needed precise and cost-effective parts for their cerebral ultrasound device. Through the high standards of our expertise and customer service, we made it happen.
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Hypodermic Tube for Delivery System

Problem

Material: Stainless Steel Hypodermic Tubing

When a production lot of critical component for an ophthalmic delivery system was rejected by a publicly traded OEM on their flagship product, supply levels of the component dropped to a point where a line-down situation was imminent. The contract manufacturer responsible for the situation reached out to KMM for help.

Resolution

Days away from shutting down the line, KMM responded by dedicating equipment and running two shifts to avert the problem. After 2 weeks of running, enough safety stock was built to ease pressure on the component, and resume a normal production schedule.

Capabilities

  • Intricate grind shape
  • Small diameter tubing size – 30 Ga
  • Tolerances: +/-.0005″
  • Secondary processes of blasting and cleaning were also required
  • 8 Ra surface finish max on ground surfaces

Spool/Sleeve Actuators for Boeing Aircraft

Problem

Material: 440C HT 58 RC min

Part match-fit and cylindricity requirements made vendors willing to accept the responsibility of holding print tolerances scarce.

Critical Dimensions

Match-fit clearance: hold match fit clearance spool/sleeve to .00005″. The resulting cylindricity on both spool and sleeve necessarily were near .000025″.4 Ra surface finish.

Resolution

Match-fit of .00005’’ was attained for customer, and all parts passed aircraft standard inspection. Project was completed and customer was awarded future orders for multiple units over the next 5 yrs.

Capabilities

  • Multi-Axis CNC OD/ID
  • Ultra Precision Centerless
  • CNC Centerless

High Precision Shaft

Problem

Material: 440C HT 58 RC min

Company in California could not find a local source for high-end aerospace shaft work.

Critical Dimensions

All diameters ground – two (2) with tolerance of .0001” total, perpendicularity to .00002” (20 millionths) and concentricity to .000025” (25 millionths) on all ground surfaces. 4 Ra surface finish.

Resolution

Parts were ground to all specs per print. The customer not only provides the above part to the end user on a repetitive basis, but also receives first right of refusal on all similar high end projects.

Capabilities

  • Multi-Axis CNC OD/ID

Missile Wing Pins

Problem

Material: 440C HT 55 RC min

A Tier-1 defense contractor rejected parts from their primary vendor for a high-end precision pin used to affix fins onto missiles. The rejection of the pins caused a delay in shipment of missiles to the Persian Gulf, and left them with no source for the pins after the primary vendor lost approved status. The Tier-1 contractor needed to ship missiles within 2 weeks otherwise late delivery penalties would be assessed.

Critical Dimensions

Diameter .19000 +/- .00003” (30 millionths), Flats and specific nose configuration, Parts needed to be manufactured “complete” in a 1-2 week time frame!

Resolution

Parts were manufactured complete in 10 days from purchasing material, blanking, HT and all grinding operations. All features were ground, including nose angle and nose radius. The diameter sizes needed to be recorded and the parts bagged & tagged to match the parts up for press fitting into existing holes in missile wings. The customer was able to keep to their quoted delivery schedule and avoid penalty.

Capabilities

  • Ultra Precision Centerless
  • CNC Centerless