Chemcut’s Blog


Our blog is designed to help teach you about metal etching, designing an etching plant, maintaining your wet processing machines, and more.

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Product Showcase: 2300 Series

At Chemcut we offer three different product platforms for wet processing equipment. We offer the 2300 series, the XLi series, and the CC8000 series. Each one has its strengths, but today we will discuss the 2300 series. The 2300 series is a model that targets the quick turn and prototype markets. Here are the four unique qualities the Chemcut 2300 series equipment has to offer.


1. Small Footprint

The 2300 series’ compact design allows it to be suitable for businesses of all sizes. With this series, you can save space while getting the productivity and efficiency of a conveyorized system.


2. Reduced Sump Size

This feature requires less chemistry on-site and allows for a quick change of process chemistries. A smaller sump also means less rinse water that will need treatment after cleaning out the machine.


3. Quick and efficient installation.

This compactness of the 2300 series means easier installation and maintenance without sacrificing product performance.


4. Scalable to large production levels.

The 2300 series technical performance is easily scalable to large volume equipment like the Chemcut XLi or C8000 series.


Conclusion

If you are looking for a chemical etching line but need something compact, easy to maintain, and cost-efficient, you should consider our 2300 model. If you are interested in the 2300 series but have more questions, you can send your questions to us here, or you can even arrange to visit our customer lab to receive a demonstration of how it works.

6 Chemical Etching Safety Tips

If you are working in the chemical etching industry, safety should be one of your top priorities. A chemical etching shop in irresponsible hands can become a dangerous place because of the many physical and chemical hazards. In this article, we will share some useful safety tips we have learned over many years in the chemical etching industry. Utilizing these tips on top of normal safety procedures and policies will ensure your chemical etching shop becomes a safe place to work.


1. Mind the edges

After etching, any edges exposed to the etching process become sharper. Because of this, it is highly recommended to handle etched panels with gloves that will be resistant to any punctures or slashes that the edges can inflict. This is more of a concern in the field of chemical etching because parts are etched through. In the printed circuit board industry, sharp edges are produced less because there is no point where the top and bottom etching meet to form a refined knife-like edge.


2. Double-check valves

Right before you perform any task with or on your wet processing equipment, it is a good idea to double-check the valves. This will ensure there will not be an accidental release or exposure to the chemistry. It will also allow you to ensure that the necessary process controls are active.


3. Don’t leave a filling machine unattended

When you are loading an etcher with water or etchant, it may be tempting to step away and do something while you are waiting. The problem here is that it is inevitable that someone will forget and overfill the machine. When a machine overfills, the contents will begin to overflow from any openings — this becomes a hazard in the workplace because of the possibility of slipping on the wet floor and being exposed to the etcher chemistry.


4. Reduce time working inside the etcher

Image of opened etcher after water testing

Working inside the etcher can be an uncomfortable part of performing maintenance. Whether you are reaching into the etcher to troubleshoot or perform preventive maintenance, it is always best to allow the etcher to cool down to room temperature before performing tasks. If immediate access is needed, it is best then to minimize the amount of time inside the etcher and to reduce skin contact with the wetted interior. Most etchants can irritate the skin and produce toxic fumes when hot.


5. Maintain a preventive maintenance program

To prevent unexpected events of exposure, it is important to perform inspections often. Always check seals, plumbing, and containment to ensure there is no compromise. Preventive maintenance keeps your equipment in top condition and prevents any sudden, accidental releases of the contents inside any wet processing equipment.


6. Understand the active chemistry

In chemical etching, it is highly important to understand your etching chemistry. Understanding what materials or chemicals may react can go a long way in terms of safety. It is easy to underestimate what reactions can occur with your chemistry. If an incompatible component is added, the outcomes can range from a highly exothermic reaction to a release of toxic gas.


Conclusion

Maintaining a safe environment in the chemical etching industry is highly important. If you follow these tips you’ll be a few steps closer to having a safer chemical etching shop.

Are you looking to make your chemical etching shop safer? At Chemcut, we offer an extensive preventive maintenance agreement that is customer-specific.  This program could be annual, semi-annual, monthly, or whichever works best for you. Should you be interested in this type of service, please contact our service department by clicking here.

How to start a chemical milling shop

Chemically milled parts

Starting a chemical milling shop works very similarly to a printed circuit board (PCB) shop with a few key differences. In a PCB shop, your only goal is to etch copper so you can receive the circuit pattern you are looking for. In chemical milling, the common goal is to make multiple parts from a metal sheet. The metal used that could be, but is not limited to, copper, brass, steel, titanium, or aluminum.  Chemical milling offers an efficient alternative to photo-electroforming, stamping, wire electro-discharge machining, and laser beam machining. In this article, we will touch on where to start planning your chemical milling shop, the processes involved in chemical milling, and what equipment you will need to complete these processes.


Where to start

In chemical milling, like any other business, you should have a solid idea of what you want to produce before you dive in. One of the most important things in this industry for you to know about your product is what material it is going to be made of. Depending on the metal you want to etch, it is going to affect what equipment you are going to need. The selected metal for etching can affect what components you need in your equipment to withstand the active chemistry. Some etchants and solutions are highly incompatible with certain plastics and metals, and thus your equipment can become seriously damaged without careful evaluation. Once you have figured out what your product is, the next step is to determine what equipment you will need. In order to run a chemical milling shop, it is necessary to have equipment to complete the following steps:

  1. Prepare – Check properties and cut sheet metal to make appropriately sized panels.
  2. Clean – Remove any materials that would conflict with the adhesion of laminate.
  3. Laminate – Apply a photosensitive coating to the panels.
  4. Expose – Treat exposed photosensitive coating with light.
  5. Develop – Remove untreated photoresist from the panels.
  6. Etch – Remove exposed metal.
  7. Strip – Remove remaining photoresist.
  8. Waste Treatment – Treat contaminated rinse water to meet discharge limits.
  9. Inspect – Evaluate if products meet specifications.

Prepare (Non-Chemcut product)

To start making your sheet metal products, inspection and measurement tools will be necessary to evaluate panel dimensions and hardness. There are plenty of measurement and inspection tools available but the ones that are the most necessary are tape measures, scales, and calipers.

If you must cut out your panels from a larger sheet, it may be useful to invest in shears appropriate for the job and to pair that with a deburring tool in case it produces sharp edges.

Approximate Cost = $75,000


Clean (Chemcut product)

Mechanical cleaner

Cleaning your panels prior to lamination is important because without removing the oils and contaminants from the surface, the photoresist laminate will lift and reduce resolution. Cleaning panels for chemical milling can be done either mechanically or chemically. A mechanical set-up could range from a bucket with a scrubber to a conveyorized brush system. Similarly, a chemical clean set-up could be complete with a bucket or a conveyorized system. Selection of which one to go with can depend on the level of production you wish to achieve, and/or the tolerance for abrasions resulting on the final product. One of the functions of the mechanical clean is to roughen the surface on a microscale to obtain better adhesion of the laminate; therefore, the chemical clean option is most suitable for cases where scratches and abrasions should be minimal.

Approximate Cost = $150,000


Laminate (Non-Chemcut product)

Dry film hot roll laminator

There are two different methods to laminate your panels — wet film and dry film lamination. The most used method of applying wet film is dip-coating. This is a method where a panel is withdrawn through the meniscus of liquid photoresist. For dry film, it is typically applied with hot rollers that compress the photoresist onto the panel. Usually, thinner resist correlates with better resolution. Thinner resist layers can be achieved with liquid resists; however, they can be more difficult to apply than the dry film. With these key differences, dry film may be the most suitable for manufacturing sheet metal parts that do not require ultra-fine lines. Selection of your laminate may also depend on the material of your panel because some resists may be incompatible.

Approximate Cost = $200,000


Exposure (Non-Chemcut product)

There are two different types of exposures — flood exposure and direct imaging. Using a flood exposure consists of utilizing a photo-tool that will cover the surfaces of your panel to control which areas get treated. Direct imaging exposures do not require a photo-tool because they utilize lasers to image the design onto the panel. Regardless of the exposure type, you will have to invest in a room with yellow lighting where exposing will be performed. The purpose of the yellow room is to utilize lighting that will not harm your photoresist while it is being stored or while it is on a panel prior to developing. Depending on the desired resolution, you may also have to invest in transforming the yellow room into a clean room to reduce the likelihood of dust particles interfering with exposure. High-resolution projects require high precision, and because of that direct imaging exposures are the most efficient in cases requiring high resolution. High resolution with flood exposures can be difficult with double-sided exposures because it is easy to have misalignment between the photo-tools. Any misalignment could interfere with attempts to etch through.

Approximate Cost = $200,000


Develop – Etch – Strip (Chemcut product)

Sectional develop-etch-strip line

All three of these processes are very similar when it comes to the equipment they need. In some cases, they are capable of being performed in a bucket, but doing these steps in a bucket is far from ideal because of long wait times, inefficient use of chemistry, inconsistent results, and lack of safeguards. Objectively, the best way to go is with a conveyorized system. With conveyorized systems, the baths can be adequately controlled to maintain solution quality. These systems can also come in two different forms — sectional models and modular systems. Sectional models are chambers that are divided into sections where everything is connected. In modular systems, instead of dividing the chambers into sections, the chamber sections are constructed and then connected to others — this allows for more customizability and process flexibility. Commonly, the develop, etch, and strip processes are 3 separate machines, but if the space is available, they can all be connected into one machine so that there is only one loading station and one unloading station. The design and model are highly dependent on your production level, process needs, and available workspace.

During the developing stage, it is important to ensure that you are neither under-developing nor over-developing. Under-developing means that all the untreated photoresist is not being removed, and over-developing means the developer solution is starting to cut under the treated photoresist.  Over-developing is problematic because it can reduce resolution, and under-developing is problematic because it may need to go through the developer again — thus leading to bottlenecks. To avoid these, it is recommended to have a breakpoint, a point where untreated resist is clearly removed, at approximately 45-55% of the develop chamber length.

At the etching stage, the most critical variable is etch uniformity. To obtain etch uniformity, the surface of the panel needs a constant feed of fresh etchant. The larger the panel, the more likely it will deviate from a uniform etch. Typically, the edges etch faster than the middle. This is because effectively a puddle of reacted etchant is formed in the middle restricting fresh etchant from reaching the panel surface. Although this is a common issue with large panels, this should not discourage you from using large panels because there are engineered solutions to this problem.

While at the stripping stage of the process, it is important to have stripper solution that is compatible with your photoresist. When stripping, the goal is to remove the photoresist in small chips. If the solution is incompatible, the photoresist will be removed as large chips, goo, or very fine pieces. These become problematic in filtration and can cause the spray nozzles to become clogged.

Having all three of these processes working efficiently is the key to running a successful chemical milling shop.

Approximate Cost = $360,000


Waste Treatment (Chemcut product)

Commonly, this waste treatment is performed as a 5-step batch process. The steps consist of holding, precipitating, clearing, ion exchanging, and finalizing. Each step receives its own tank, but generally the precipitating tank and the final tank are the largest. The holding tank serves the purpose of collecting contaminated rinse water that will be sent to the precipitation tank whenever enough has been collected. The solution is then treated to precipitate heavy metals out. It is important to note that depending on your etch process, your precipitation method may vary.

Once the metals have precipitated out of solution and settled at the bottom of the tank, the water on top is decanted into the clear-well. When the water level gets closer to the precipitate, the rest of the tank contents are fed into a filtration system such as a plate and frame filter press.

When it comes to waste treatment and disposal of hazardous waste, such as the precipitate, it is also important to obtain a discharge permit and to plan a course of action so your hazardous waste can be treated. Heavy metals and other hazardous contaminants in the water are usually regulated and have limits, so it is important to receive a permit and understand what local and state regulations you must meet.

After transferring treated water from the precipitation tank to the clear-well, the water then needs to be checked to ensure the contents meet your permit limits. If the contents do not meet your limits, the water can be sent to the ion exchange tank so it can be treated with an ion exchange column. Once the limits have been met, after precipitating or ionizing, the treated water can be sent to the final tank.

Approximate Cost = $350,000


Inspect (Chemcut product)

Once your panels are completed, it is good practice to frequently check the quality. Some of the tools commonly used for quality evaluation are microscopes, calipers, pin gauges, and micrometers. These tools are all used to manually check the qualities of the final product, but there are also automated inspection tools that can be implemented into the process. The automated options can become expensive, but they offer the benefit of high production rates and consistent production quality if they are integrated with process controls.

Approximate Cost = $75,000


What is the next step?

Once you have planned out your equipment and determined your chemistry, photoresist, and materials, the next step is to reach out to the suppliers. Any additional questions you have, they should be able to clear up because there are plenty of people who enter this industry with little experience. Any supplier who is familiar with the industry should be able to guide you through every step of the way. The resources are available out there for you to learn, so why not use them to your advantage?


Conclusion

The total cost to become a fully equipped and functional chemical milling shop is approximately $1,700,000. Undoubtedly, going into the chemical milling industry is a big commitment, but all the upfront investment, planning, and research pays off. There are plenty of resources on the topic of chemical milling and photochemical machining so please do not feel discouraged. We are here to help. If you have any questions, feel free to contact us. If any of those questions pertain to the wet processes such as cleaning, developing, etching, and stripping, our whitepaper, “Guide to Photo Chemical Wet Processing Equipment”, goes further in depth with the equipment capabilities.

Thank you for reading! We hope you found this article useful for your journey into the industry.

Innovation in Chemical Etching – 5 Areas to Expect Growth

Chemical etching ties into many different industries. Automotive, aerospace, medical, semiconductor solar, electronics, and many more industries produce products by chemical etching. You are probably using something that was produced by chemical etching right now. This is why the photochemical machining (PCM) industry is so versatile. Whenever this industry innovates and grows, so does the technology it feeds into. In the 1950s, chemical etching revolutionized printed circuit boards by providing an efficient, economical method to produce reliable electronics. How could chemical etching revolutionize technology again, and what changes should we expect in chemical etching? In this article, we will talk about the 5 areas in chemical etching where we can expect innovation.


1. Process Simplification

There is always room for improvement when it comes to simplifying process equipment. The more accessible the equipment becomes; the less hassle preventive maintenance and operation becomes. Etching can be a simple process, but when you are using it to commercially produce parts or circuits, more constraints and challenges come along and lead to more complex systems. A simplistic design that gets the job done can go a long way.


2. High Resolution

Obtaining higher resolution means being able to produce more precise and complex designs. With etching finer features, comes the challenges of consistently meeting narrow tolerances. Many of the limiting factors to high-resolution etching occur prior to the etching process.  It is critical that items such as proper artwork compensation, thickness and consistency of photo-resist application, precise alignment of the top and bottom side artwork, and the resolution and capability of the imaging equipment all be optimized to achieve high-resolution etch results. Even something as small as a speck of dust can result in a reduction of the resolution of the etched part. Clean rooms rated class 10,000 or better are required.


3. Undercut

With the trend of designs becoming more complex and packed together, Undercut has become an issue that limits resolution as you increase etch depth. If undercut was completely eliminated, you could theoretically obtain a feature of any size with any etch depth. The main problem with undercut is that it is desirable to have a fast etch rate to maximize production. However, the typical trend is that whatever results in higher etch rates, also results in more undercut.

Some etchants have been used to try to reduce sidewall etching by forming a complex with the sidewalls, but it still has not gotten rid of the issue of undercut. Sidewall etching can also be reduced by controlling the crystalline structure of the metal. Controlling this is aspect however can be an expensive and challenging process. In the near future, It is entirely possible a new form of etchant or method to control crystalline structure can come about to efficiently reduce undercut.


4. Etch Uniformity

Etch uniformity is also another area in chemical etching that can cause growth. As manufacturers try to maximize production, there will be a shift towards using larger panels to get more parts per panel. However the larger the panel, the harder it is to maintain a uniform etch. This difficulty in etch uniformity comes from what is called “The Puddle Effect”.

Diagram of "The Puddle Effect" on a panel.

This effect describes the lack of diffusion on the surface of the panel due to the formation of a puddle in the middle. The puddle inhibits a uniform reaction by creating a barrier between the fresh etchant and the surface. Because of The Puddle Effect, the edges of panels etch faster than the middle. This tends to be less of a problem in chemical milling because you etch through. Uniformity in the printed circuit board industry, however, can more challenging to achieve.

There have been many attempts to overcome this problem, but the best solution currently is “intermittent spray”. This is a solution developed by Chemcut to overcome the deviation caused by The Puddle Effect. It is considered the best because it minimizes deviation without any loss in production rate, transport capabilities, and equipment simplicity. Intermittent spray achieves this by creating a targeted etch in the middle of the panel to compensate for the difference on edges.


5. Thin Material Transport

In the printed circuit board industry, there is always a drive to obtain thinner, flexible material.

Transporting thin material is a challenge in chemical etching. This is because the panels need enough open space to be sprayed with the etchant. The downside here is that when there is open space, there is a chance for the leading edges to deviate and cause wrinkles and folds. There is a balance that needs to be met because as you fill the conveyor with transporting aids, you lose etching efficiency. That is because it becomes harder for the etchant to reach the surface. Not only do you lose efficiency, but you also have to worry about etch rates differing on the top and bottom.

A common approach to solving this problem is to attach a thicker board, known as a leader, to the leading edge of the thin material. This prevents the front end from getting caught anywhere in the line. The problem with this method is that it inhibits production rates and requires someone to manually attach and remove leaders. This is why many people in the chemical etching industry seek thin material transport systems that do not require leaders.

Due to the wide variety of thin materials and substrates that are currently available, it is not practical to rigidly define the thinnest material that etching equipment can transport without leaders.  A general guideline for minimum thickness is less than 1 mil (.001 inch, or 25 micron).  It is recommended that materials below this guideline be submitted to Chemcut for testing.  Perhaps in the near future etching equipment will be able to effortlessly transport even thinner material.


Conclusion

There are plenty of areas where we will likely see the photochemical machining industry flourish. A breakthrough on any of these 5 could be a big game-changer in technology because overcoming each one opens up new opportunities. At Chemcut we are always exploring new ways to improve the wet processing side of these areas. If you interested in what ways we are working to innovate wet processing, please feel free to send your questions here.