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Quality Considerations In Photo Chemical Etching

Quality issues are of paramount importance in photo chemical etching (PCE) because the precision of the etching process directly affects the final product’s accuracy and reliability. Photo chemical etching is a subtractive manufacturing process that involves removing material from a metal sheet using a chemical solution and a photoresist mask. The process is capable of producing intricate shapes and patterns with high precision, making it a popular choice for manufacturing components in the aerospace, medical, and electronics industries. However, any deviation from the precise design specifications can result in the production of defective parts that can compromise the functionality and safety of the final product.

To ensure the highest level of quality in PCE, strict process controls must be put in place, and each step in the process must be carefully monitored and inspected. This includes controlling the temperature, concentration, and agitation of the etchant solution, ensuring the proper exposure and development of the photoresist mask, and verifying the accuracy of the etched features using sophisticated metrology equipment. By maintaining tight tolerances and consistent quality standards, manufacturers can produce reliable and high-quality components that meet the exacting requirements of their customers.

Michael Kern, Head of quality Management at leading PCE innovator micrometal, discusses quality and how the company meets the exacting standards its customers expect.

Q: What does quality mean in micrometal?

A: Quality is at the heart of what micrometal does as a company. We are a service provider for all kinds of customers across industry. Therefore, it is necessary for us to satisfy the challenging demands of highly globalized concerns as well as smaller companies. It is our belief that only with the maximum level of quality can we fulfill our promise to be a reliable and long-term partner for our customers.

That also includes our contribution to their manufacturing processes, as our performance will have a huge impact on how efficiently over a long period of time their assembly lines will operate without incidents. There is another very important aspect. We want our customers’ products to “look” perfect. This means our quality standards ensure customers’ products are as durable and trouble-free as possible throughout their lifetime.

Furthermore, the products that we produce are far from the usual parts fabricated from metal. Instead, they are often geometrically complex, and need to be produced with maximum repeatability, and this can only be achieved efficiently with PCE.

Q: As micrometal focuses on large volume applications, what does this demand of your quality control regime?

A: Imagine one defective part or section on a reel one kilometer in length — taking hours to produce — and resulting in the reel needing to be scrapped. Also, we usually do not have one reel being produced at any one time, but several reels simultaneously in a continuous process, meaning we cannot just simply stop production. We cannot remove the defect and continue.

Therefore, to maintain efficient production, we need effective control measurements in all areas. We have established a highly reliable supplier base, with our business partners delivering the most precise and high-quality raw materials suitable for our process.

Our self-designed and produced tooling is created with decades of expertise under our belt, and can be optimized inexpensively to achieve the highest repeatability and best etching conditions.

Our process is controlled in-line and live all the time to prevent defects and keep a huge amount of process variables in the small window of tolerances, which are needed for our next generation PCE process.

But PCE defects cannot be totally eliminated, and so we have the technologies to detect defects during production and take counter-measures to keep the yield high.

As our market-leading PCE process is pushing the boundaries of what is possible with etching, quality control technologies are also operating at the edge of their capabilities in a production setting. Because of this, we undertake 100% inspection of our products in a downstream process so that we can be really confident that we have achieved the quality we promised our customers.

Q: How much of your quality control takes place in process and how much “in lab” or is it a combination of both?

A: Roughly put 50:50. As I mentioned before, we make a lot of measurements during tooling construction and production to control the process. But it is simply not possible to control the huge output of our line in situ for all features and dimensions during a continuous, “breathing” PCE process.

In the downstream 100% inspection process we then have the time and technical ability to control everything that is needed.

Vice versa, the production crew will benefit from the experiences and monitoring data from the 100% inspection in the next production run.

Q: What do you mean by 100% inspection?

A: 100% Inspection for us is a downstream quality process, in which we conduct all necessary efforts to check every produced part again with the best technologically available resources, so that every single small deviation from the desired product state is detected and controlled accordingly. We conduct it to achieve maximum repeatability, reproducibility and reliability of our product output.

Q: Are you able to claim zero failure rates for customers, and if so how?

A: First things first in etching, like in any other production method, there can always be a deviation. But, with all control methods put into place we minimize failures as far as is technically possible.

During the design and sampling phase we will co-engineer and agree upon a failsafe method with our customers to either remove defective parts from the delivered batches or mark them accordingly, so that the highly automated assembly lines of our business partners will detect defective parts with maximum reliability and control them accordingly. This is real zero failure.

Q: How do you think micrometal’s view of quality differs from standard PCE providers?

A: I don’t think there are standard PCE providers, as everyone providing this service is special.

However, what makes us unique is the sheer quality of our etched parts. We have compared lots and lots of competitive products, and no one can achieve such smooth features, such small tolerances and hence such quality precision metal parts like we do.

Whichever way you look at it, PCE is still a chemical process, the variables in the process having the ability to produce parts that are not entirely what the customer expected. Where other PCE suppliers might accept this, we will tweak tooling, process parameters, and all control measures until the desired results are achieved. 

Q: Is the move when it comes to quality towards total automation and the reduction of human intervention?

A: Micrometal is closely observing what is possible with technology, and we do see some future potential in total automation. So far as our next generation PCE process is on the borderline of what is technologically achievable, total automation is still not possible. What is done, of course, is eliminating the human factor wherever possible at every possible process step. We have risk analysis and optimization methods installed, which – based on lots of gathered data and experience – will identify and prevent technical pitfalls by putting failsafe technologies and practices into place.

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