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Grinding machine for removing welds on steel weldments?

Econdron

Hot Rolled
Joined
May 31, 2013
Location
Illinois
Is there anything like this that exists? Here's a picture of a product we make:

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Flap discs and grinding wheels just take too much time. I've been able to speed up the cutting process and the fit up/welding process on these, but the grinding is just something I can't seem to come up with anything. The grinding on these can easily take 2-3 hours for a set. I would love to find a machine where I could drop these in, have it knock down the welds to almost flush, then go through and blend in by hand.

The picture above is just one example, there's 70+ different shapes and configurations we make, the ones in the picture are just the most complicated. We make displays and furniture products, those are table legs in the picture. Most products are painted or powder coated after completion.

My first thought was a Blanchard type grinder, but I've never operated one, so I don't know how long they take or what their cost-to-operate looks like, or if this would even be a good application for that type of machine. Thoughts? Or just stick with the tried and true hand grinding method.
 
GTAW (TIG) weld, less grinding. :) yea I know, prob not gonna happen.

No blanchard grinding wouldn’t be good, not at all. The alignment of welded stuff like that is not good enough to allow it, and the machine would be enormous.

Cubitron 11 is all you need to know.
 
What's your budget ?

yeah I know, your poor....BTDT

Timesaver conveyor belt sander ?

I have a Timesaver, 36" W, 2 heads, NC controls, wet model. It doesn't work as well as you would think, even with Cubitron II 60+ grit belts. We use it mainly for polishing stainless, so it could be because the roller is too soft. It's been a while since the contact roller was redressed, but I seem to remember going a little harder than recommended on it so we could easily rip through the pits on the mill finish stainless bar stock. I want to say its around 70 duro? It also requires the welds on one side of the leg to be mostly ground down, otherwise the welds on the conveyor belt side of the machine can really mess up the machine. Don't ask me how I know.
 
Dynafile makes contact wheel with a 1/32" riser wheel so you can be aggressive at first then smooth it out. I haven't used it myself though

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If your going to paint or powder coat, could you weld with an undercut then use filler that is powder coat comparable? If that’s not possible, weld with undercut, fill the rest with brazing. You could then knock the brass down with a router with a carbide bit. Is it the perfection you are looking for with metal finishing? Probably not. But, it is a way to speed up production. Now some good folks will say this is a “Hack” way to do this. How many milling machines and lathes were built with filler to the castings?
 
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I have a Timesaver, 36" W, 2 heads, NC controls, wet model. It doesn't work as well as you would think, even with Cubitron II 60+ grit belts. We use it mainly for polishing stainless, so it could be because the roller is too soft. It's been a while since the contact roller was redressed, but I seem to remember going a little harder than recommended on it so we could easily rip through the pits on the mill finish stainless bar stock. I want to say its around 70 duro? It also requires the welds on one side of the leg to be mostly ground down, otherwise the welds on the conveyor belt side of the machine can really mess up the machine. Don't ask me how I know.
Gee, I don't keep up on your soap opera.

Might have tried listing in the OP what you have already tried eh ?..:nutter:
 
Heck, just go to brazed joints. Plenty strong, easy to control, easy to blend down when needed or build up again. I'd presume your fitment is pretty good to start, so that shouldn't be an issue. If you need more heat, TIG braze.
 
GTAW (TIG) weld, less grinding. :) yea I know, prob not gonna happen.

+1 on TIG welding it. If you have the skill, you can even have a model where you leave the welds on there and charge the same price as the polished ones.
If you’re grinding flat and polishing, then the weld prep needed for TIG isn’t an issue. The decreased productivity will be greatly offset by the decreased grinding time. But you need more skill for TIG welding.
 
Use a 9" angle grinder with a 3M Cubitron II fiber disc 36 grit (the really thin ones on a backup pad). The heat from the spark stream feels like lava when you're getting at it.
 
Also, don't be afraid to change them out when they start to wear down. The lost time and increased fatigue aren't worth it.
 
Can you show us a picture of what these look like before the welds are blended to get a better idea of what you are up against? I would think that 2 hours from welds to fully blended smooth part is not excessively long depending on the finish required of the final part. If it takes 2 hours to blend all the seams out I also think that the two flat sides are only 1/3 of that time at most, and replacing that portion with another process wouldn't add much benefit.

What abrasives are you using, but more importantly how often are you changing them out? If you are blending both of those two parts with 1 80 grit flap disc that is why it is taking 3hrs. Abrasives are expensive, but the time is worth a good bit more so I change them out frequently when doing this type of work.

I would MIG this, then blend with Sanding disc - Flap disc - DA sander in that order. (inside fillets run a clean bead so no sanding is needed) TIG would be more pleasant for whoever is doing the work, but I don't believe it is an efficient use here and wouldn't save any time over all.
 
You need better welders...I seen all this---lay on a fat bead so there are no "Tram Tracks" when its ground,grinding excess weld off takes ages.......Find a welder who can run a decent flat weld bead with zero undercut.
 
Given these do not seem to be life supporting structural then the material should be prepped such that the full weld is still lower than flush.

Proper V cuts at mating parts with correct wire size and speed should mitigate most of your problems.

If the V allows for full thickness of material to be seen before welding then the weld will easily be almost same thickness of the material without being above it.

Requires a good skill set welder as well as proper preparation and fixtures to hold it.

Time better spent doing it such to not need to remove as much material.


Simple puddle welding with oxy torch would do it but slow.

Another vote for tig

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Get better abrasives. Buy disks (hard stone or paper) made for stainless, they are tougher and they hold up longer on normal steel. They also grind quicker.
With proper abrasives, I could sand that weldment flush in around 5-8 minutes or less...
I would also likely want to have 2 grinders, one with a quick removal and one with a finishing setup.
They make disks ( the name escapes me) that are a flapper wheel style disk that have (I think) a 120 grit abrasive and various types of scotch brite style pads layered on top of each other. They were awesome at finishing stainless/steel and you could damn near do the whole job in a timely fashion on aluminium, rough weld to finish ready for paint in around 30-90 seconds... The life of the disk was shorter on the aluminum welds but they were still worth it.
Second, get better at MIG. That is not a part that is worth the effort of TIG, its too big. Just get your joint setup and process dialed in to just barely fill to the toes of the weld with a slight crown at the center. The right abrasive will make the crown at the center disappear in seconds and blend into the base metal shortly after without effort.
 
Maybe try putting 'skids' on either side of a handheld belt sander so that when it's sitting on a flat surface it doesn't quite touch the surface...

That way you can put the skids on either side of the weld line and apply as much pressure as you like to get it close to flat without worrying about gouging the underlying steel!
 
A stroke sander with a hard contact wheel and then a flat platen might get you part way, but you are looking at a 5k-10k machine if you can find one used (with the contact wheel) or 20k new. Most of the used stroke sanders out there don’t have the contact wheel option so make sure you can mount one if you find a cheaper used one.

We dress welds like these for similar items and use cubitron II fiber disks in 36, 80, and a 3m pale blue “cut and polish” scotchbrite disk made for powder coating prep. Hit me up and I’ll send you one to try out.

Unfortunately there is not simple solution. Getting your guys to used the correct abrasive and lean into the grinder is where it at. I know everyone recommends big 7-9” grinders but they are way to heavy and large to use for 8 hours a day and not have shity results. Set up your grinding station with dedicated grinders for each grit.

Are you pre finishing sections prior to fully welding. Simple work holding can help too we use engine stands, it allows the legs to be flipped easily.

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