Improving Standard Operating Procedures for Powder Coating Operations
Expert Rodger Talbert says be sure to use instant feedback to let the operator know when a problem first appears.
Q: We have pretty good standard operating procedures, but we still have problems with light coating, orange peel, gun spits and other issues that cause rework and scrap. Are there any good ways to create guidance for our workers so they can troubleshoot their issues, keep the line running and reduce coating defects?
A: As you have discovered, it is fairly simple to get someone reasonably competent with a powder gun and able to coat most parts with an acceptable level of quality. However, several factors influence the consistency and overall first pass yield of the process. The complexity of the part geometry, type and color of powder being applied, “fatigue” factor and volume of parts passing through the booth may have some impact on lowering the consistency enough to generate the kind of problems you describe.
For starters, I would try hard to have operators get some formal training from an outside source. Many powder coaters learn internally from the other people on the line. We sometimes joke that the new guy learned from the old guy who learned from the older guy who learned from the dead guy. That may work, but you can see that if anyone in that chain had some bad habits then those will be passed along and the new man or woman on the line may not have all of the knowledge they need to understand how to adjust and best use the powder gun. Try looking for training programs from the Powder Coating Institute (PCI) or Chemical Coaters Association International. Look for seminars or webinars that you can access. Talk to your powder equipment and material suppliers to see if they offer any training or if they are connected to associations that conduct programs. Consider getting a consultant to come in and conduct line coaching. Whatever works for you, get some outside help to refresh the knowledge base.
Next, be sure that your operators get a good understanding of how to set up and troubleshoot their gun. Set up an internal trainer who has good skills and a clear understanding of electrostatics and spray technique, and give them an opportunity to work with the new people. They may be able to add to their own knowledge using books from PCI or online sources. This internal trainer is a key employee, so be sure they have the right incentives of wage and benefits so that you can retain them to maintain the link of historical knowledge of your products, powder materials and powder equipment.
Be sure to use instant feedback to let the operator know when a problem first appears. If the quality staff or unloaders notice a light coat, they should pass that information along right away so the trainer can work with them to show them how to correct the problem. This is not an exercise in criticism or blame, but a process for learning and continuous improvement.
Lastly, try to learn what your coaters need in terms of incentives to stay with you. Understand the need for wages, benefits, time off, transportation or whatever it takes to keep them. It is not always possible to compete with other job offers, but do your best. And be sure you have a good understanding of system efficiency (another subject that requires training) and that you are getting the maximum margin from your system. Otherwise, you will not be able to compete and you will forever be training new people.
Improvement of a Powder Coating Batch System
Q: We operate a batch powder coating line, been in business for three years and want to improve our operation. When we started, we bought some used equipment that included a powder booth with one spray gun, a blast booth and pressure blast system, and one oven. Can you give us some guidance on things to consider to help us decide where to invest in a better system?
A: It is hard to know just what your priorities should be without seeing what you have, but I have seen hundreds of batch systems and I have some idea of the challenges you face. Let’s start with how to plan a system. You should make some determination about the largest part and the volume of batches that you would like to be able to run. You should look at how much room you have (or would like to have eventually) and how the largest batch size could easily flow from one station to the next without slowing you down or choking the space. You should list all of the limitations of the current operation and consider ways to eliminate or improve the operation for maximum production and efficiency. This blueprint can serve you for the decisions on what to add or change.
Next, look at part preparation. You cannot blast some metal gauges and blasting is not always effective when you have organic soils (heavy grease for instance) that are hard to remove. You should definitely consider a wand washing system that gives you at least three stages of operation — cleaner/phosphate, rinse and seal rinse. That will allow you to handle those lighter gauges of metal and get off the oils that are common on cold roll steel parts. You will need an enclosure with a drain for the wash operation and you will need to check on local rules regarding the handling of wastewater from the operation. Be sure to make the enclosure large enough for your production goals and largest batch.
Look at the time it takes to complete each step in the process. Typically, the coating operation is faster than the cure oven. That means you need to have enough oven capacity to keep up with what you coat. And with the addition of a wash operation, you should consider adding an oven to dry parts so that you do not use too much oven time for drying when you need to be curing. Also, remember that the cure oven can be large enough to handle more than one batch load and that could be a real help in keeping up with coating.
Make sure the current powder booth is large enough to handle the volume and the largest part you want to be able to handle. If it is not big enough, you should add a second booth that better meets your needs. Be sure it is large enough and also make sure you have good airflow to keep the dust down while coating, and that it has good lighting to make it easy to see what you are coating. Two booths may be a great asset for handling different products and increasing productivity.
As you look at the flow of product, make sure to avoid bottlenecks and avoid excess cart movement. You may want to consider a hand push rail system to allow you to move things with less handling and smoother flow through the process. Look at the cure oven and determine if it would be best to have doors on both ends to facilitate movement and allow more loads to be staged at the entrance end.
Make sure you are properly staffed and that the operators are well trained and supervised. You will have multiple operations, including part preparation, coating and curing. You may have masking or special handling. Make sure you have the right crew to keep things moving and get it done right with minimal rework. Best of luck with your future operation.
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