Even though the operators are skilled and trained to operate in tube mills, there are still some challenges and issues that they need to face every day. Tube mill owners should arrange training sessions on how to troubleshoot the problem and figure out what was causing the problem. If these problems are not addressed properly, aluminium fabrication, steel fabrication, or stainless steel fabrication processes won’t have precise tubes and pipes to work with.
Today’s let’s explain some of the most frequent issues you face and the causes behind it.
Lost Mill Time
There can be a number of causes for excessive downtime for a normal operation or job or tooling. The main cause behind it is the absence of written procedure on the setup. This written procedure can help operators to control the overall process and even help with troubleshooting at times. That’s why not having one written can be a big issue especially the only variable of the mill setup equation is the manual control factor.
Secondly, having no setup chart can also be an issue as the tooling should be done as the way it was meant to. So, having no setup chart will only cost a lot of valuable setup time.
Sometimes even the lack of any formal training can be an obstacle to minimize setup and execution time. This is true for all manufacturing as well as metal fabrication processes.
Other reasons behind the loss of mill time are a disregard of all the parameters from the previous setup, poor mill condition, misalignment, poor tooling condition, etc.
Weld Zone Split
Too narrow strips with inadequate material to forge is one of the main reasons for weld zone splitting. Also, like any manufacturing process or laser cutting, plasma cutting, metal bending, metal rolling, and other metal fabrication processes, misalignment can cause issues to the overall process.
Poor split’s edge, improper fin passes, non-parallel edges, strip’s off-center approaches, improper chemical steel compound are the other few reasons for weld zone split.
In the sizing section, there will be times when you’ll see irregular sizes occurring which is mostly due to the improper setup of the welding section, fin, etc. Also, if the forming part of the machine sends improper formed/sized tubes, irregular sizes may be the result.
Apart from that, the bent in the shaft or the oversized holes in the tooling can be the culprit for irregular size. To be honest, there are literally hundreds of reasons why the resultant product can have unusual sizes but it’s not possible to name all of them here. But if any of the reason above doesn’t fit as the reason behind irregular sizes, try checking the driven shaft’s ODs or ensure (1) the weld size is in accordance with your setup chart, (2) round weld size, (3) smooth weld scarf, (4) parallel side rolls, (5) proper cooling of the tube, (6) parallel strip edges, (7) tight bearing, (8) properly installed rework shims, etc.
Weld chatter is another common phenomenon that you see very often. The main reasons are insufficient weld bed or upset, inadequate weld power, dull knife or insert, faster weld cooling, a good distance between the weld box and scarf stand, etc.
Also, strip rolling and tube marking in the Breakdown section are another two most common challenges that operators need to face. But these two are their own thing and I’ll cover that in another article with detailed information.