A LeanWerks “Better Process /  Better Part” Case Study  

Materials, features, and tolerances are individually,  and in combination, the source of manufacturing  challenges and uncertain outcomes. The ultimate  challenge is a part that combines all three, and this  Thrust Brace is an exceptional trifecta.  

Challenge  

• Material: 410 Stainless Steel or Inconel 625. Both  are not considered “free-machining” alloys.  Inconel, especially, develops high temperatures  during machining operations that alter the alloy  microstructure, and potentially induce residual  stresses that can degrade fatigue life of the  component and/or distort the final geometry.  

• Features: Varying cross section from thick to  thin requiring large amounts of material removal  and potential distortion from stress relieving.  

• Tolerances: True position and size tolerance of  the holes are both less than .001 inches –  exacerbated by their location on the end of the  thin sectioned wings, which is where heat and  distortion from prior operations will have  maximum impact.  

History  

By the time LeanWerks was introduced to this part,  the customer had low expectations as prior suppliers  had not found a way to successfully address these  challenges. Previous builders forced the customer to  compromise some objectives because the parent  assembly did not fit together with the designed fit through the tight tolerance holes in the thrust brace.  The customer had two options: 1) relax the tolerance  on the holes and sacrifice design performance, or 2)  buy extra thrust braces and conduct time consuming  and expensive sorting activities to best fit each thrust  brace with each assembly.  

Solution  

“All solutions are simple” – A mantra and an ideal at  LeanWerks. Starting with a foundation of great  people that include journey level tradespeople and  degreed engineers, then strengthened by application of a comprehensive integrated job launch process,  LeanWerks develops effective manufacturing plans  guided by this simple solutions principle.  

In this case, two wire EDM operations, each with a  rough and finish pass to accommodate stresses that  relieve during material removal, create a  

geometrically perfect exterior from raw stock. Then the part is restrained in a rigid fixture inside a five  axis machine so the holes can be installed in one  work-hold with exacting precision. It’s that simple –  and effective.  

Results  

Thrust braces that meet specification, every time.  That’s the result we expected and achieved.  Improved production and material yield, fewer labor hours per part, and a happy customer were also great  results. However, the best and completely  unanticipated result was that this thrust brace, which  is part of a down-hole tool for oil exploration, caught  the eye of a potential aerospace customer who has  since become a regular customer.