All About Alloy Management: Part 2
All About Alloy Management: Part 2
Last month, we began talking about alloy management in a small and defined scope in terms of things laboratories can do to become more efficient and profitable. This month’s alloy-related topics are no different: casting methods used on a daily basis, extraction considerations and scrap alloy refining. What we do in each area affects our profitability and productivity in the alloy-based arena.
The Line on Casting
Despite our success in limiting our alloy choices and its positive impact on how we managed our inventory, we found that our casting techniques were well somewhat archaic. I’m talking about using a wind-up casting machine a typical centrifugal force machine that requires someone to wind it up, get a torch and heat it with an oxygen/propane technique. Though used for decades, this method is problematic on several fronts.
First, when you cast an alloy using this technique, because you’re hitting it with a torch, there’s no way your eye can visually tell you if the alloy’s reached 3,000 degrees or 3,200 degrees. All you’re looking for is whether or not the alloy looks melted, and that’s subjective. Technicians typically over-heat the alloy because if they under-heat it, the alloy won’t be fluid enough, won’t cast completely and the result is a mis-cast that now requires soldering or rewaxing and recasting. Unfortunately, when alloy is overheated, an oxidation of the desirable properties of the metal occurs, leaving it other than in its true desired form. The bottom line is this: When you cast with a torch, your alloy is never quite as good as the manufacturer intended it to be.
As a result, the rule of thumb when casting with a torch is that whatever the button weight is whether one penny weight or 10 penny weights you need to add 50 percent new alloy to refresh that button’s properties so it won’t become too brittle. After all, when it becomes too brittle, it will break or crack or otherwise ruin the restoration and create problems. But, the cost of 50 percent more alloy can add up!
So, we invested in an induction casting machine by Reitel, which was roughly $20,000 and we immediately noticed two distinct benefits. First, our castings were always dense, strong and solid. As a result, we experienced fewer rocking bridges and fewer castings that required soldering.
Secondly, because the machine casts so accurately and there is no centrifugal force and hence no spraying out of alloy we’ve found that we don’t need to add as much new alloy. Instead, we weigh the wax sprues with the alloy on them, multiply that by the specific gravity of the alloy and then increase our penny weights by one or two to ensure that we’re getting the smaller button, but still a successful cast.
We now use less alloy per casting. In fact, we’ve found that we’re using an average of an ounce and a half less of metal per month by using an induction casting technique. That’s roughly $600 that’s being saved per month! So, the machine is actually paying for itself through the alloy we’re not using.
Laboratory benches that we’re sold often feature an accompanying extraction system that will likely be recommended for a certain number of technicians. In our laboratory, however, we have configured our workbenches and extraction system to be double what’s recommended. For example, in the area where metal finishing takes place, that technician is working under an extractor strong enough to service four people. Why? The alloy is very heavy and, as the technician grinds it, particles of gold are flying in the air. Well, the better the suction system, the more gold that is captured.
What’s more, if you haven’t invested in a good vacuum system, consider doing it now. You’ll find it will pay for itself. How? Well, I’ll use my laboratory as an example. Every year we end up getting back about 8 percent of what we buy in alloys. We get it back through refining of the extracted scrap and the great thing is we get paid for it in cash.
Cashing in on Scrap Refining
There are many alloy refining companies out there and it’s important to work with one that’s reputable and has a long history in the business. When we collect and bag our alloy scrap, one of the companies we use for refining is Ivoclar Vivadent.
To maximize the return from your scrap, you should identify the source of the scrap and facilitate collection at the source. Once the alloy scrap is collected, it should be separated and identified according to its quality. To facilitate scrap recovery and ensure an accurate valuation and, hence, payment similar types of scrap should be placed in strong plastic bags that are labeled with their description and then placed in a sturdy container. Scrap bags and containers are available directly from Ivoclar.
In this column and last month’s, we’ve tackled the tough subject of alloy management from several perspectives. What I’ve shared have been some of the things that have proven successful for my bottom line, and I hope they can be helpful to you, too.