|Ask the Experts|
March 26, 2014
Wave Solder Pot Alloy Adjustment Formula
Test reports indicate we have a tin level of 62.04% and a lead value of 37.96% in our 63/37 leaded wave solder pot. The solder pot capacity is 300KG. How many KG of pure tin should we add to the wave solder pot to restore the alloy to 63/37? Is there a formula to follow?
|Expert Panel Responses|
Theformula for adding pure tin to restore the alloy to 63/37 is: W(Sn)= (0.63-0.624)*W(ap)/0.37 W(Sn):Weight of tin need to be added; W(ap): Weight of alloy in the pot. Forexample: If you have 280 kg alloy in the pot now, the pure tin added would be: W(Sn) =(0.63-0.624)*280/0.37 = 4.54 kg
Director New Product Development
Metallic Resources, Inc
I'llassume that you have room in the pot to make a small addition without firstremoving some. We will be adding pure tin, so the total amount of lead in thepot will remain the same. We know that after the addition, we want the percentlead to be 37.0%. So we can calculate directly the total mass of solderrequired to meet the goal:(37.96%/37.0%)*300kg = 307.7838kg Thedifference between the starting mass (300kg) and ending mass (307.7838kg) isthe required tin addition, in this case approx. 7.8kg. It's normal for the percentage of tin to drop over time because tin willbe lost at a higher rate in dross than lead. So we will occasionally have toadd some pure tin. You can minimize corrections by adding some pure tinperiodically. Track how much pure tin you need to add in total over a longperiod (say, six months) to maintain the proper tin-lead ratio, then determinehow much would need to be added per week. Institute a weekly addition of alittle less than this amount, and track again. Optimize as necessary.
|Submit A Comment|
Free Newsletter Subscription
Circuitnet is built for professionals who bear the responsibility of looking ahead, imagining the future, and preparing for it.
Insert Your Email Address