23 Jan Heat buildup on orbital weld head is slowing production – how do I troubleshoot this?
[Full question here] “We have a team welding 6 inch OD 316L tubing with a .109 wall thickness. Using the AMI 207 with their 7500 weld head and water cool, they are experiencing excessive heat such that production is being slowed to only 5-6 welds per day. Can you suggest some methods to help cool the head better, or some other method to speed production without having to coupon in each time?”
[Answer] You should definitely be getting more than 5-6 welds per day on a coupon. If it’s burning up the tungsten after 5-6 welds, then it may not necessarily be a heat issue. It could be that you’re using poor quality tungsten.
If it’s not the tungsten, then here are some options to consider when heat build-up is slowing production:
1- Located on the CSI cooling unit, directly below the power connections, is a mechanical flow-meter. When the pump is on, and fluid is passing through the system, the impeller in the flow-meter should be rotating too rapidly to count. Does the “flow-meter” indicate adequate flow is occurring? If not, the blockage needs to be cleared.
2- One way to reduce the amperage needed to produce a good weld (full penetration), and therefore the heat generated, is to replace the 100% Argon purge, with a mixed gas purge. Using a 95%Ar +5%H blend will allow approx. 15% amperage decrease. A 90 Ar/10H mix allows a ~25% reduction. The lower current setting results in less heat generated. Gas blends are traditionally more expensive, but can help to address the issue (there are other benefits of gas blends as well).
3- Purchase specialty designed collets for 6″ OD material that have cooling flow ports designed into them. These will act as “chill blocks” on either side of the weld, assisting in removal of heat from the work area.
4- The use of a “High Production” Weld head such as the Magnatech 860 head that offers superior cooling has been recognized as the greatest advantage to this challenge. Weld production from 5-6 welds per HOUR are specified from the manufacturer. This type of head is currently being adapted by CSI to interface with AMI and Swagelok equipment using our special cooling system and will be available this summer, 2013.
This kind of an issue (multiple variables) probably warrants a discussion. Please contact CSI for a consultation on the matter.