Hello Thor, you've got your work cut out for you as I'm sure you're aware. Spatter is generated for an infinite number or reasons and scenarios. There are literally hundreds or thousands of different types of wire filler metals on the market, even a change in the manufacturer of the same grade, diameter and type of wire can have an impact on the amount of spatter that is noticed.Type of shielding gas can have a significant impact on the amount of spatter that is generated(there are many different types of gases used for shielding with many different percentages of these that can be mixed to achieve certain arc, weld characteristics), diameter of filler wire can also have an impact on spatter generation. The type of metal transfer that is occuring can impact this quantification, ie; short arc, globular transfer, spray arc, and pulse arc. If you are including FCAW processes then you can increase the number of variables since dual shield wires to date can be run with CO2, 75/25, and some with 90/10 shielding gases, innershield wires also fall into this category(they are the self-shielded flux-cored wires), here again wire diameter and volts, amps, wire speed all can affect the spatter generation. I haven't even touched on gun angles, pulling or pushing the puddle(with the same machine settings and just changing from pushing to dragging can alter spatter generation greatly). Grounding and arc blow issues can also greatly affect amount of spatter that is encountered, if you aren't quite sure what I mean by arc blow, I would simplify the explanation by saying that since the welding that is taking place is utilizing a DC current with electron flow in one direction there can be a magnetic field generated that will act on the arc in a detrimental manor. Incorrect parameters when welding with any process can have a significant impact on spatter characteristics. I might suggest that you could modify the topic of your paper to cover the topics that I have touched on in this response, it might have more meaning than trying to count the amount of dingle-berries that happen when a weld is made(I am trying to add a little humor here). Hope this helped some. Regards and best of luck, aevald
I have conducted many of these experiments. Spatter loss is a very important and costly part of high volume manufacturing. In the auto industry, 500,000 pounds of GMAW wire per year per line is not uncommon. In most stainless steel products such as exhaust components the wire can be as much at $2.90-3.00 per pound. Even a well developed pulse spray or well controlled short arc can still be loose as much as 1-3 % in spatter. Using the numbers from above 500,000 pounds at 1% spatter loss is still 5,000 pounds per year and at $2.90 per pound is almost $15,000 per year on the floor. Now multiply that by 2 or 3 major lines.....you see where I'm going. No plant wants to see that kind of money lost without charging it on the piece price of the part. Therefore in order to be competitive in the automotive segment, knowing exactly how much is lost is very important.
You can start with the simplest (not super accurate, but works) by doing a weld booth experiment. Clean the booth from top to bottom to remove any foreign material. Then test weld a given size plate or plates at set parameters. Remove all spatter from the test plates in the booth. Now clean the booth again with a very fine brush and weight the spatter you have collected. Find the weight of the wire per inch or foot. Using the wire feed speed and arc on time, determine the amount of total wire used. Subtract the amount of spatter connected and determine the % of loss. Now change one variable at a time and repeat everything to get the spatter loss difference for any given variable.
Good luck.....Use patience.
Mark
Hello Mark, I applaud your attention to detail concerning weld spatter, and it certainly does make sense when you are talking the types of quantities that you list in your post. That does somewhat bring home the need for assessment of welding consumables, brands, parameters, shielding gases, and other associated factors. It should also open the eyes of those shop management folks that insist on using C02 shielding gases because they only see the cost of the gas and not the associated periferal costs such as clean-up,spatter loss and the like. Thanks for giving me a different perspective relative to this topic. Best regards, aevald
I have never done a test as you describe, but I was wondering. Would it not be easier to weigh the filler metal before welding and after to get the consumption, and also weigh the test plate before and after to get the amount of metal deposited?
That would also take into account the weight of slag, fumes, smoke and etc. when the difference is calculated. Or is the intent to also differentiate spatter from other waste?
Chet Guilford
I have to agree, why differentiate the spatter?
Proper welding techniques eliminate the greatest percent of spatter. Why not pre-qualify the procedure to reduce the spatter to minimum? Why be quantitive with a nonessential variable?
Best regards
Vonash
By THOR
Date 03-20-2006 05:57
Thanks alot for your help, i was thinking along the same lines as you as far as calculating the data for % lost, but instead of using a weld booth, i built a copper box to completly enclose the welding process to make spatter collection easier, to keep the spatter from sticking i used a spatter release spray inside the box and performed all the welds using a motoman NX robot. if you want, give me your name so i can properly source your help in my references as i am presenting my work to the Canadian welding associations toronto chapter in a couple weeks
See the articles by M. J. Kang et.al. Welding Journal Jan. 2001, and Sept. 2003.
http://files.aws.org/wj/supplement/Kang01-01.pdf
http://files.aws.org/wj/supplement/09-2003-KANG-s.pdf
That's about as technical as it gets!
Chet, Vonash, you are both totally right. The original post only listed spatter as a subject for research, total process efficiency is something more in depth. I was also only looking at the GMAW process where slag is non-existent and smoke/ fume loss is not a high enough loss to calculate. I also agree 100% with Vonash that proper techniques can almost eliminate spatter, however it still exists.
The type of welding I am using these studies for are robotic welding of small automotive components. That is repetitive for 300,000 parts per year or more. Many of these processes do not have consistent fit up and most do not follow any AWS codes, other than the 5.X's for filler. 10 inches of weld in 1 plane in space is long in this industry and .080" material is considered thick. Nothing is pre-qualified, and most OEM's consider everything an essential variable, regardless of what the AWS code states. Not that I agree with that. That's just how the big 3 (or 5 it might be soon) operates.
Yes i agree, looking at that total process effiecny would be alot more indepth but it is not my intent with this experiement. I just want to look at the amount of welding spatter being produced. I think with this info, parts manufacturers who have issues with spatter sticking onto threaded holes or other spattersticking problems, would be able to evaluate differnt welding procedures and process to asses which ones would have the least amount of spatter being produced. Looking at the processes effiency would sorta tell me that but not in a precise way.
THOR, you've answered my question. You have quite a task ahead of you- what with testing all the variables that affect the production of spatter.
I don't know if this will help or not, but I would try doing as Mark suggested. Only- I would set up a "mini" test booth to make spatter collection easier.
You might want to contact some filler metal manufacturers to see if they have already done some studies on the subject.
Chet
