We have talked a great deal about photo etching "rules of thumb" and general design guidelines. And, these guidelines apply to the vast majority of the work we do. But, the rules aren't necessarily absolute. We have been able to solve some very delicate problems for customer applications by adapting chemical etching process elements to achieve much greater precision and control.
These adaptations are outside of standard process parameters for photo etching and required a fair amount of engineering effort and testing. We were successful in achieving very tight dimensional tolerances (+/-.0003") and a consistent and repeatable process for scaling up production.
In this particular case, we were fighting the inherent efficiency of our photo etching process with it's predictable and consistent rate of material removal. The "sweet spot" for this application was mere seconds. Given our automatic system for regenerating the etching chemistry, there really is no waiting for spent etchant to buy more time. But that thought triggered a new plan.
By changing the rules of our standard process, we were able to remove the time pressure and gain a tremendous amount of very fine control of the process which made it possible to meet the requirements of this etching application. The customer's response was elation, as this had been a very thorny problem for them.
And, yes, it does cost more than a standard chemical machining process, but the yield improvement for the customer more than offset the increase in the production cost of etching, as well as substantially reducing their burden of rework.
The lot-to-lot consistency of this process may soon allow them to drop the 100% inspections to a 2.5 AQL, saving nearly $2 per part. Although cost saving was not their primary motivation, they will not mind it one bit.
We are very pleased that we were able to find a unique and effective method to meet the customer's requirements, and in a way that we know is controllable and repeatable day after day.
This is one of the ways that we are willing to go beyond the conventional wisdom of industry practices to solve complex and challenging customer problems. It helps a great deal that we have a tremendous pool of knowledge, experience and talent within the company who have the insight to think differently about demanding projects. In some places, as this customer experienced, they were simply told that what they wanted/needed couldn't be done.
So, if you have a project that some have said couldn't be done, give us a call (800-443-5218). Or send me an email,