The single, most important, factor to be considered when purchasing barrel plating equipment is understanding that the equipment you’re buying is part of a system. Your plating line is a kind of an “industrial ecosystem.” Every component—barrels, tanks, rinsing system, etc.—affects the results generated by every other component. Short change one piece of equipment and you’ll pay the penalty further down the line. This principle applies to both new equipment purchases or the repair and retrofitting of existing plating lines.
Plating is a competitive business and platers will try, understandably, to get an edge on the competition by cutting costs any way they can. Too often, where these costs are cut greater expense occurs elsewhere.
In an effort to maximize production and reduce cost, platers will wait until a barrel “goes down” to repair or replace it. However, that barrel was probably inefficient long before it broke down, costing more in rejects and reduced production.
Many times we will see a barrel come into our plant for a drive shaft replacement when the cylinder has drastically peened over perforations. Replace the drive shaft and put that cylinder with its peened perfs back on the line and you’re going to experience continual plating problems due to poor solution exchange and huge dragout issues.
Recently, we had a call from a customer who sought some advice. He was running an acid/tin line using barrels with 3/64-inch perforations and a wall thickness of ¼ inch. He was getting dull finishes and found that his barrels were “floating.” He asked if he could add weight to his barrels to force them down into the solution. During the plating process he had instructed his operators to lift the barrel out of the solution, drain it and resubmerge it to replenish the solution inside the cylinder. His rectifiers were showing big drops in current. He reduced the load size to compensate. Reducing the load size reduced his production.
Adding weight and resubmerging the barrel in the process tank were quick, cheap fixes, but he was paying the price in low-quality, dull plating. He was treating the symptom, not fixing his problems.
What turned out to be the root of his problem was incorrect use of the barrel. What had happened is a common occurrence in a typical job shop. As work is being run, the next available barrel that comes into the load/unload station gets used, regardless of the parts to be run in it. This creates a mismatch. Parts are run in a 3/64-inch perfed cylinder when they should have been run in a cylinder with larger openings. One run with the mismatched parts was enough to peen over the 3/64-inch perf and “seal” the fate of that cylinder.
here were other factors contributing to his problem. The ratio of wall thickness (1/4 inch) to the cylinder openings contributed to his current-distribution problems The peened-over openings were increasing his dragout.
We replaced his cylinder with a new one that had a 3/64-inch perf and a much thinner 1/8-inch wall. To attack the problem of running mismatched parts in the wrong size barrel, the new cylinder was convertible. It allowed the operator to exchange the wall panels of the cylinder with inserts of different size and shaped perfs to match the parts being run.
We were on hand to watch the “new” cylinder make its maiden voyage. Carrying the correct load size and parts that matched the perfs, the cylinder made its way down the entire line without once floating off the hoist pickups. Furthermore, the rectifiers no longer were experiencing the drastic drop they previously demonstrated. His parts were brighter and contamination was lower. By putting his money toward the root of the problem, he had saved in the end.
As with any eco-system, the root of the problem needed to be eliminated before the whole system can function efficiently. The entire plating line needs to be analyzed and careful consideration must be given to what effect a single component will have on it.
In today’s regulatory environment, water and waste treatment are areas in which most shops are looking to cut expenses. Careful consideration must be made as to how these expenses are cut, so they are not just shifted to another area.
A customer recently was running a nickel line and getting parts that were “cracking and peeling.” His rinsing method was rather unique. He was employing four counterflow rinse stations that were timed to operate only when a barrel would enter a rinse tank. He was running four loads per hour. The rinse station would pump five gallons of water per minute for a one-minute duration only when the barrel was in the tank. His profits were up and his costs were well in check. But, the plating suffered. Customers were upset and began to return work. In an attempt at a quick fix, he began to run more water over longer periods of time in each station. he increased dwell times over the process tanks to reduce dragout. As a result, he was no longer getting the loads per hour to which He had become accustomed.
The root of his problem was in his rinsing scheme. Improper surface preparation due to inadequate rinsing was causing the poor quality plating. Lets do the math. He was running five gallons per minute for one minute, four loads per hour. That amounts to a 20 gallon per hour “turnover” rate in the rinsing tank. Lets say that each load yields approximately 3/4 of a gallon of dragout. At four loads per hour, there are three gallons of dragout per hour entering the rinse tank. This three gallons of dragout is diluted by 20 gallons of water per hour. That’s an incredibly inadequate seven-to-one rinse ratio, (20/3) considering the recommended prescribed rinse rate is 5,000:1.
Even without doing the math, its not hard to see that pumping only 20 gallons of water per hour in a counterflow rinse tank quickly results in a heavily dragout saturated rinse. The money saved in water was more than offset by the cost of reruns and rejects.
We were able to solve his problem by installing a spray rinsing system that uses recirculated rinse water. The rinse unit delivers five timed, programmable-duration sprays. These sprays are delivered to the load both outside the barrel and from within the cylinder via a spray nozzle. Each spray is made up of consecutively cleaner water. The last spray in the cycle is fresh water. The small amount of dragout rich water discharged during the first spray of every cycle was returned to the process tank to compensate for evaporation losses. The new system used very little water, but yielded incredibly high rinse ratios. It used only four gallons of water per barrel and since the cycle took only four minutes that station could now potentially handle 15 loads per hour. Since the rinse unit was able to accomplish this in a single rinse station the plater was able to eliminate three rinse stations and replace them with three more process tanks, increasing his production by 400%.
In conclusion, whether you buy new equipment or upgrade and retrofit your current system, step back and look at the big picture. Do the math, figure all your costs carefully. Don’t be lured by the quick fix that will, in the end, cost you more.
