The Project
When one of our longtime medical device customers needed support to move their latest project from the prototype level into small lot “pre-production,” they called on High Tech Turning. This customer had a completed design for a novel, minimally invasive surgical tool and had proven it out at the prototype level using their internal machine shop to create the parts. Now, they were preparing for a clinical and trial they needed a run of 200 parts.
The part was tiny – nearly the size of a grain of rice – and made from heat-treated 17-4 stainless steel with some very tricky geometry and tight tolerances ranging from +/- 0.0020” to +/- 0.0005”.
The customer had originally machined the prototype in several operations on their CNC milling center. Additionally, it had required significant manual deburring work and we knew that needed to be minimized in order to be cost effective.
When they were ready to enter “pre-production” for the clinical trial, they turned to High Tech Turning. Why? Because they know our experienced team can machine parts like these in one operation on our advanced Swiss CNC lathes, and our process-focused mentality is what they need for high-volume manufacturing. HTT also has the capabilities in our inspection department to verify the parts meet specifications and can produce the dimensional data they need for the FDA.
The Solution
Although this part had been proven at the prototype level, some of the geometry was not practical to recreate in a high-volume process. Our solution started with teamwork: HTT’s manufacturing engineers shared insights about best machining practices which allowed the customer’s engineering team to make design for manufacturability (DFM) improvements that would make it possible for HTT to complete the part in one step and remove unnecessary manual secondary work.
With the customer’s new design in hand, our machinists developed programs for our CNC Swiss lathes and designed a customized tooling plan to make it all possible.
Once the parts were machined, our inspection team verified that the geometry had met all of the tolerances using our CMMs with touch probe and vision capability. In addition, the inspectors re-verified the CMMs’ output with physical gages and calibrated micrometers, something we always do for tightly-toleranced parts.
This required a significant investment of time, but the benefit was we were 100% sure of the accuracy of the results, and we were able to output data directly from our CMMs for every part that was measured. This data was shipped with the parts and ended up being invaluable to the customer as they worked with the FDA to receive approval for their device.
The Results
High Tech Turning continued to support production on this part and ended up shipping over 9,700 parts in the next 3 years. Our customer also utilized HTT’s “Just-In-Time” stocking system meaning parts arrived at their door within 48 hours of their request.
HTT’s design for manufacture advice proved invaluable and the customer’s new design performed even better than the original.
Every part specification was achieved, including dozens of tight tolerances ranging from +/- 0.0020” to +/- 0.0005”, and a burr-free 16 µin Ra surface finish.
We successfully produced the first 200 pieces within six weeks, including heat-treating, CNC machining, tumbling, cleaning, and passivation, plus generating “100% inspection reports” for 30 pieces.
Our customer’s clinical trial was a success and their design was cleared for production.
