Change from FCAW to GMAW

By Sberry

Date 11-23-2011 21:09

Is the weld itself a 3/8 or is this the material thickness? How much, a bit or all day? How many machines?

By Mac L

Date 11-23-2011 21:23

The weld size is 3/8 (avg). The material is also 3/8. The welding is 24 hrs a day on 16 machines.

By Sberry

Date 11-23-2011 21:35

One more question that may be helpful, does the vert need to done with the same machine?

By Mac L

Date 11-23-2011 21:39

If possible, yes, but not necessarily.

By js55

Date 11-23-2011 21:53

Depending upon your alloy, assuming carbon steel, metal core is probaly a better way to go for the flats because you get deposition rates close to flux cored without the slag clean up issues.
This won't work on the vertical stuff though but then niether will solids in spray.
You need to evaluate whether or not the increased cost in wire balances the decreased cost in efficiency.

By fschweighardt (***)

Date 11-23-2011 22:26

I would look at solid wire in a nice hot spray for all of the flat, stay with FCAW for the verts. If you have water cooled guns and welders who do as they are told, 1/16" in spray is impressive

By Metarinka (****)

Date 11-23-2011 22:38

I will mirror what most say. Also from having spent sometime evaluating costs of welding processes generally material costs is not a significant factor. 90% of the time the more efficient process in lb/hr or joints an hour will win. I would also look at mechanized if you haven't already, we could generally justify it on anything longer than 3 feet, but this is dependent on a lot of variables. As an example I can usually push mechanized past 20"/min and up the deposition rate, the best manual welders generally never make it over 7"/min.

I would say metal core would be the way to go for flats probably not gonna get further than you are now with FCAW, is the switch because of wire cost or cleanup?

By Sberry

Date 11-23-2011 22:57

One of the reasons I didn't toss my 2 cents in was I really don't know much about it in the respect of the numerous options but 16 machines running around the clock is worthy of some real investigation as to production/cost. There has to be a mountain of slag laying around here, that alone could add substantially to cost, cleaning the product and mess, huge amounts of smoke, etc I would have to guess that someone should have looked hard at this before now considering the amount of manpower involved.

By Metarinka (****)

Date 11-26-2011 07:40

I would agree it's always good to evaluate the process costs of welding if you have multiple machines/welders. However generally consumables cost is not a driving factor in welding cost. For all the drills I've ran, I've never seen consumables cost be greater than 20% of the total cost. As mentioned hidden costs such as extra slag removal, clean up, defect rate etc should be evaluated if possible. Labor and overhead is the meat of welding cots. If you have a wire than runs 5% faster but costs 30% more I would be willing to bet it would still be cheaper.

By ozniek

Date 11-24-2011 11:04

Hi Mac

The major issue with GMAW is lack of fusion defects. Technically in spray and pulsed spray transfer this should not happen, but unless there is relatively tight control on the welders, you will always get the guy that goes to dip transfer because it is easier to control. This can easily lead to LOF defects. I do not know what product you are making, but in the case of relatively critical products, many companies will not allow the use of GMAW, for this precise reason. Obviously if you are making a product that does not really have end-user QC involvement, it just becomes an issue of making sure that the systems in your shop are such that you get good results. This can certainly be achieved, as long as the right procedures and discipline / motivation is present.

Regards
Niekie

By makeithot (***)

Date 11-26-2011 02:23

There will be no real cost savings in my opinion mainly because the process is slower and the QC issues will increase. It can be done but I think the cons out weight the pros. I use both but not because one is cheaper then the other.