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Up Topic Welding Industry / Technical Discussions / valid testing parameter ideas for cost saving change on GMAW
- - By Mwccwi (***) Date 11-05-2008 23:28

looking for valid testing parameter ideas for cost saving brand change on GMAW electrodes. We are looking for a way to reduce electrode cost spending, managment wants to change from a years trusted [Lincoln]wire to something cheaper. I'm concerned that in changing wire for cost saving we may burn ourselves. I understand to look for packaging (for frequency of change-overs, tip, liner, drive-roller consumption. But I need guidence on setting up valid defendable testing, so that I/we know that we are not losing quality or hidden efficiency with things that are hidden buy the obviously cheaper wire. I don't wast to get screwed.

Links to other tests
Ideas from personal experiences
Sample testing procedures sheets
on-line access to similar studies or articles
any help will be greatly recieved
Parent - By aevald (*****) Date 11-06-2008 00:57
Hello Martin, you've possibly got a bit of a tough one there, depending upon who you are trying to convince on this. I believe you already hit on the packaging item, I recently had some conversations on this very topic. In my discussion with an ESAB rep. he, in fact, did say that the wire cost was greater for the bulk packaging option, yet the end cost was reduced by the greater efficiency and lack of changeover time, etc. As to justifying one wire brand over another, there are certainly some marked differences in some cases, yet some of these differences might need to be dealt with by altering gas mixes, changing welding parameters, and possibly a number of other variables. If you are simply changing from one brand to another, everything else being equal, you may not end up with the same results. In some cases the change could be a more positive one and in others it may go the other way. At the same time, if the change goes badly there could be a parameter, shielding gas change, or other alteration that might take care of the negative issues.
     If they are simply trying to cut cost then there is a possibility that going to one of the metal core wires might even be a consideration. Certain situations will justify this type of wire very well, it typically has a higher deposition rate and when it is properly applied will yield very nice results with respect to bead profiles, lack of spatter and other finished bead traits.
     At the school here we typically use a couple of different types and brands of wire for our specific needs. In order to come up with our choices we have tried many different types of wire, in most cases we will request a sample roll and then install it on one of the machines and the students and instructors will put it through it's paces with regard to positions, parameters, and finished bead appearance. It then gets a "rating" of sorts and we decide whether we will consider a change. Gotta run right now Martin, I'll see if I can get back to this a little bit later when I have some more time. Best regards, Allan
Parent - By aevald (*****) Date 11-06-2008 06:30 Edited 11-06-2008 06:33
Hello Martin, back again. Definitely pay attention to the S-ratings on the wires so that you aren't comparing apples to oranges. Visuals will tell a fair amount about the quality of one wire compared to another; does the bead wet-out on the toes properly and if not can you make adjustments to the parameters that will take care of this? Are the visual bead profiles acceptable for your application and can these be readily changed by adjustments of the welding parameters or operator application techniques? Is there any excessive spatter and if so, can this be addressed with parameter changes and if this is the case do these changes match the requirements of your applications? Is the work that you perform done strictly on "new" materials or does the work incorporate both new and old? Some wires are much better suited for one or the other and still others might be very tolerant of both. If you are wanting to get rid of excessive spatter, can this be done in the short-circuit mode or spray transfer mode if both of these are being used in your production needs? I mention this in particular because some wires may work very well in the spray transfer mode and yet when they are operated in short-circuit transfer they may have unacceptable amounts of spatter, others might be the direct opposite and still others may work equally as well in either mode of transfer. A lot of what you are up against appears to be coming up with ways to provide evidence of quality of one choice of wire over another and possibly being able to show these differences to others who may not have a full understanding of these differences and what they could mean in terms of quality, cost, and possibly liability. You might even consider taking this a step further and include tensile testing, various types of NDT, and possibly sectioning and etching samples to further support a particular choice of consumable.
     I mention all of the above not to say that you haven't considered these items for your current production regimen but more so to do some comparisons for "their" choices of less "costly" consumables and providing evidence of why they might not be suitable. Hope some of this might be helpful. Best regards, Allan
Parent - By SWP (**) Date 11-06-2008 15:08
One quality factor of the wire to look at, one that can cause immediate, severe, detrimental effects, is the cast and helix of the wire, and the consistency of cast and helix from spool to spool.  Several years ago my employer ran 30 automatic weld stations, each with a 1000 pound spool of Lincoln E70S-6.  Initially, we struggled with inconsistencies in the wire cast, it varied from around 3' in diameter to dead straight.  We used straight MIG guns, so the straight wire did not give good contact, we needed consistent cast of around 3 - 4'.  Once we identified the issue, Lincoln was all over it, we agreed on a specification for cast, they took back all the wire that was outside the spec., and they began supplying cosistent spools within weeks.  That was excellent customer service, and true proof of commitement to product quality, both very important factors that some bean counters may not understand when comparing price.

I would guess there could be other factors such as the wire surface finish, residual drawing lubricant, variations in the copper coating, etc. that may vary from one manufacturer to another.

When looking at a new supplier, consider going to their warehouse, sample many spools and measure the cast and helix.  At the same time you can visually inspect the care in packaging, the surface of the wire, wipe the wire surface by dragging through a clean white cloth, etc.

My guess is that mechanical properties will not be an issue from one source or another, but rather the issues may be consistency of wire feedability and arc inconsistencies do to some of the factors listed above.  These things are difficult to quantify, since you may have to run portions of many spools over an extended time period to run across a problem spool.  As you do run your machines, data on tip life can relate to the wire quality.  We ran CWT Arc Data Monitors on all our machines, and it was pretty clear when our contact tips were worn out by watching for a rise in voltage and arc length, which in turn related to potential weld inconsistencies.  Without data acquisiton, you could still monitor tip life.

To evaluate issues of customer support, delivery, returns, etc. I guess you can ask for references and talk to the supplier's other customers.  Mark down one positive review for Lincoln, from me.
Parent - By Metarinka (****) Date 11-07-2008 20:49
I don't have much experience in electrode selection, but I did a large amount of cost cutting and quality analsyis based on shielding gas so I thought I would chime in.

I'd thought I get this off my mind first; consumables are a very small portion of costs for manual processes. Without knowing the specifics of your situation, I apologize if any of this information is redudant or not applicable. Often times managers will look at consumables first as they are the most obvious area of welding cost. Wire that is 10% cheaper offers an obvious cost saving difference, especially in facilities who average hundreds of thousands of pounds of filler material use per year, but consumables are generally much lower than 20% of total welding cost and therefore even a 20% difference in wire cost would only directly reduce welding cost say 2-5%. Therefore it is important to relate consumables to the much bigger factor of total welding costs like arc-on time, deposition rate and weld quality.

with that being said I decided to test consumables based upon the impact they had on overall process flow and the effect it had on such variables as: weld quality, deposition rate, travel speed, acceptable parameter range, ease of use, and overal performance under various average shop conditions. I found that it was much more important to evaluate consumable performance based on these parameters than on cost alone.

Futhermore if the process has not already been optimized, by means of maximizing filler deposition rate, increasing travel speed, minimizing distortion or spatter  and other methods, than introducing a new consumable will not accurately highlight it's realistic cost impact.

For my project of evaluating shielding gases first I measured and maximized the performance of the existing product. I.e the highest realistic travel speeds, deposition rates and weld quality that could be expected under actual shop conditions. Then I recorded and monitored parameter ranges i.e min max voltage, short circuit transition voltage, spray transfer transition voltage etc. Some parameters such as travel speed, etc were averaged over multiple welders to A) check for deviation and B) give accurate samples of realistic parameter ranges under shop conditions. If a WPS calls for a WFS between 275-315 and all welders are welding at 275 then it's time to evaluate the procedure. Finally macro tests and other destructive tests where performed in order to give a realistic sample of weld quality.


The same tests were run under the new consumable and the results were compared. This meant modifying other parameters etc and restablishing realistic acceptable parameter ranges and discovering any weld quality issues (O.O.P performance, consistency etc). The prime variables we were looking at were deposition rate, travel speed, penetration and bead quality. In our case the cheaper shielding did offer a reduction in consumables cost, however the practical limit for travel speed and deposition rate were lower. Therefore by increasing consumable cost by a considerable amount (using more expensive gas) we could reduce overall cost. These cost savings would only be realized if we kept our process optimized (i.e ran parameters in the range above what was achievable under the old consumable). This is where the focus on welding skill, parameter selection and process optimization overrides consumables cost.

Testing two identical consumables from two manfacturers however might not be as conclusive as the changes in quality and parameters I would think would be smaller and less noticable. Futhermore consistency issues might not be apperant if for example they only appear on 5-10% of the spools. However the methodology should be the same
I hope that helps
Up Topic Welding Industry / Technical Discussions / valid testing parameter ideas for cost saving change on GMAW

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