Hey Rob, with all of the different selling prices and different concentrations used from one resist strip supplier to the next, how do I know whether I am getting the lowest operating cost?
That is a good question. It can be very confusing as to whether you are getting a good deal or not. Each supplier has different unit costs and different concentrations and each bath performs differently. One product may have the lowest selling price, but could be used at a higher concentration or not last as long, could therefore end up costing you more. This makes it hard to determine overall lowest operating cost.
Here is what I do. I focus on loading in mil-sq.ft./gallon of concentrate. It is the best measurement that takes into account each suppliers’ price and concentration and puts the emphasis on the life of the bath or loading. You need to determine how much resist in mil-sq.ft. can you load per gallon of concentrate used before the bath is spent.
Loading: 10,000 panels run x 1.5 mil film x 70% area = 10,500 mil-sq.ft.
Cost: 20 gallons of resist stripper used x $12.00/gallon = $240.00
Cost/mil-sq.ft.: $240.00 / 10,500 mil-sq.ft. = $0.023/mil-sq.ft.
Shop based on cost/mil-sq.ft./gallon of concentrate and you will never make a bad decision.