Need advice on mass finishing machine for large parts

Greetings,

So the problem this week is deburring without making my deburr crew completely insane.
As some of you know, we make hand saws. Fret and coping saws. They're laser cut from 6061 sheet. Currently being deburred by the cutting house, at significant expense. We don't have the people or space to bring that in house.
These are the best hand saws on Earth, and we want to make sure they look the part, so the finishing is a serious concern. Which makes it slow, expensive, and leads to a lot of rejects. Which bottlenecks production, and drives up the prices.
Clearly, I'd like to get that down. Largely because we're starting to see serious price spikes in the cost of the aluminum, and the best way I can think of to hold our prices is to cut out the cost of all the handwork in the finishing. (That, and it really is a boring, tedious job that's making the crew that does it *nuts*. They'll still have jobs without the saws.)

Natrually, I'm thinking of mass finishing. Especially since the frames have a lot of internal cutouts that need their edges deburred. The problem is that the saw frames are "C" shaped, almost "G" shaped. So if you put a bunch of them in a tumbler, they lock together like those old monkey puzzle toys, and just form a big rolling rat's nest.

So my questions are two.
A) Anybody got any ideas on things to do to the blanks so they don't monkey puzzle themselves together? They are nested together when cut, so leaving a 'bar' across the open end isn't available. (And wouldn't work anyway. Tried it already. They just nest differently.)

B) Any suggestions for what machine to use?
We already have a large (20cf) torroidal vibratory finisher, but believe it or not, it's not big enough for the saws. Some of them are about a foot across, long way, and the ID of the trough of the ring isn't big enough, nevermind that it's nearly 7 feet in diameter.
I've been thinking of one of the large barrel machines, because they don't care so much about whether or not the parts have nested themselves, but my experience with those machines at jewelry scale is that they're much slower than the torroidal vibes.

Anybody used the big boys? As much as I'm terrified of the *cost* of loading one of those bastards with steel shot, has anybody used one of the big ones loaded with steel burnishing shot? Because that'd knock the corners down right quick. (as it broke the bank too...) The goal here is to break the edges, and unify the surface finish. It's got to feel good in the hand.

So I'm looking for suggestions. Like I said, from my point of view, big (10+CF) barrel machines seem like the only practical answer. Anybody know different?

Regards,
Brian

PS-->I've attached a photo of some of the frames in their blank state. And before anybody asks, no you can't get them in green. The production saws will always be red. The green ones are the acceptance masters, it's just they're the only ones I had pictures of in 'raw' state.

Have you looked into steel shot type equipment that is used for engine / motor parts?

Years ago my side gig working at a Big A automotive parts store we had a machine big enough for (2) big blocks...either clamped parts in or used a cage for smaller stuff worked really well...

Or

Dedicated CNC to debur

A robotic arm set up with an abrasive wheel or belt sander would go through those tirelessly and efficiently day and night without complaint. Only complaints might be from accounting and finance when it comes to purchasing the system...
Another thought would be to have a number of them clamped into a fixture for tumbling that would prevent them from becoming a jumbled “monkey chain”

Spruewell said:

A robotic arm set up with an abrasive wheel or belt sander would go through those tirelessly and efficiently day and night without complaint. Only complaints might be from accounting and finance when it comes to purchasing the system...
Another thought would be to have a number of them clamped into a fixture for tumbling that would prevent them from becoming a jumbled “monkey chain”

Click to expand...

HI Guys,
Yeah, I've looked at getting a small CNC for deburring, and/or some sort of jig for tumbling. The problem is the same for both: 99% of the part is visible in the finished product. So there's nowhere to hang on to it that doesn't show, and/or wouldn't be in the way of a cutter if CNC deburring. The humans can shift their grip on the fly. Point to the humans. Unfortunately, they get bored. And then we get rejects.
Maybe some sort of vacuum plate fixture with a nest for the CNC, but we need to hit both faces of the outside cuts too, not just the windows. Which is what's got me looking at tumblers. With the CNC, that chamfers the edges, which is great, *but* we still need to work on the faces to get the finish uniform, so it's only part of the battle.
I started out as a jeweler, and if these things were the size of a belt buckle, it'd be easy: dump them in a large vibratory tumbler and go to town. But scaling that up, you'd end up with a vibe 15 feet across. Which I'd buy in a heartbeat, if I could find such a thing, but they seem to top out at around the size of our existing machine.
Thanks for the help so far, it really is appreciated.
Brian.

PS--> Js, do you recall the name of whatever tumbler it was that could do two engine blocks at a time? Any details? That sounds like the right machine, if I can find one like it. (It also sounds like *WILD* overkill for an autoparts store. Wonder why they had it?)

If they are aluminium, a controlled time immersed in caustic soda then a good neutralization and wash.

Andrew's idea sounds the most efficient, but what kind of finished products would you get from that?

You could fix up a vacuum table and run them thru a time saver, but it sounds like whoever is in charge is a cheap bastard. What's it cost you to have them done manually?

They make machines specifically for deburring laser cut parts, and they work well.

I got a Timesaver Speedbelt, (which is a 52" belt sander technically for wood only I think, but aluminum shouldn't be an issue) at an auction for $6600, but I won't have it hooked up until Wednesday. Once I have it running I can show you some pictures of the parts and see if you think that would be satisfactory.

If it turns out a regular wood belt sander works nicely I would suggest getting a little grizzly model that can be had for cheap. It should last long enough to become something the company can't live without, and management will be forced to buy a proper machine after it dies.

Caustic etch will not debur a part like that, it might clean up some of the oxidation or "burns" from the laser, but the edges will remain quite sharp and not too user friendly, also removing some of the surface defects will require long etch times, which is quite wasteful, and etching should be done prior to anodizing (which looks like the final finish for the part). What could work is if your anodizer has a (electro) chemical polishing setup, but it also may take long time (thus be expensive) to remove all surface defects that the laser cutting produces, but it will debur the part.

Azmachining mentioned time saver type machine - those will work, though might be tricky to run that shape through, what I've personally used for this sort of work (low volume) was Pferd non-woven drum (without the sandpaper flaps, just the scothbrite type material) on a polishing machine, with some care the finish comes out pretty uniform, run a part like that in both directions will remove all burrs in the cutouts, my guess is it would take around a minute to sand a part like in the OP.

here is a vid of sanding half way to see the difference, the material is 10mm 6061 laser cut, this method will not remove deep scratches (bottom of the part near holes), but will hide most of defects.

Hi guys,

Well, the cheap bastard in charge would be...me. It's a long story, but I ended up in charge. Go figure.
So convincing management isn't the problem.

We have run them through a timesaver. Gives a pretty good grained surface to the faces, but hones the edges to razor sharpness. What we're really after is a nice soft broken edge, so they don't feel sharp when people put their hands on them. They're hand saws, so that's important. )
I've done some work with those little 3M disk wheels that look sort of like bristle brushes sticking straight down from the disk. If it comes down to it, one of those on a robot arm may work, but I have to believe a tumbler would be faster and cheaper than that, even a monster like I'm contemplating.
Hand finishing is OK, and it's what we've been doing up until now, but we're seeing enough growth that we can't stay with it long term, nevermind the production bottlenecks and cost. (Several dollars per part. I've *got* to get that down.)

Thanks,
Brian

Please bear with me on this guys

I'm thinking a long box trough that with the length in the X axis it shakes to and fro in the Y axis

The Y axis is long enough to take the longest frame + end clearance, think slotted panels front and rear say 2 to 3 '' deep and wide enough to allow plenty of clearance around the thickness of the frames for the media. .like a toast rack???

Frames are placed in matching slots - with the vibe running it will be easy enough to push them down through the media - and leave it to get on with the job.

There are 2 companies that you should call and get a rep in to look at your problem
SWECO, the vibratory company
Tiimesaver, the flat sanding company.
Have a bunch of un-deburred parts for them to take as samples. Many parts similar to yours are run through vibratory machines. The shape of the bowl or tanks makes a big difference. You may run through a vibratory first and then sand flate for appearance.
JR

Could you make a rack that mounts them side by side with brackets on the rack to keep it centered. Clamp onto parts hidden by the handle.

Edit, I see a rack was already mentioned

You might want to take a look at this process. I had parts tested a while back with this. They weremedical implants and the only reason we didn't choose this was because of regulatory compliance. It worked like a charm.

Deburr Edges of Flat Surfaces, Through Holes, Blind Holes, Intersecting Holes & Inside Corners

I vote for a pass under a wire drum. I'd look for a drum sander, then look for a wire drum to put on it. One pass on each side should smooth things up.

You may have to watch the "depth" of the wires and adjust as needed.

Is your volume high enough to consider precision cast the part..We did that a the big shop and cut out all most all machining on one part.
You should have posted a photo on the saw..I had to go to your site to see it.(Knew Concepts)

What is your tool life..A special cutter with proper rake to a .020 bevel would pull the chip/burr into the OD portion and so remove the burr. I would have to think about the design.. Oh and I am not making specials any more so not not me for making it.....

but.. They're laser cut from 6061 sheet. What perhaps 75 IPM?.... Cutter would be used on a CNC mill or the like...

what is the average De-burr/bug time per part?

Alberic, you describe a "time saver" that runs sand paper rigid drums or belts, or sand paper flapper wheels, those will leave a sharp bur, I'm talking about non-woven drums in the same sort of deburring machine, the finish on aluminum is very different with non-woven abrasives, it is very soft and nicely rounded corners, finish on the face is like in the video I posted, the top of the part is raw, just as cut by the laser, and the bottom is finished with coarse non-woven wheel. If you have found a wheel or a cup that works on your part used by hand, you simply need to chose the type of time saver that mimics the same motion of abrasive over the part.

Vibratory deburring takes a lot of time by itself (not counting the initial investment in the hardware), and the geometry of this particular part is not great for that either, maybe instead of separating the parts, you could screw them together to form sort of a sandwitch of something like 10 parts with spacers in between so the media can access everything, and tumble that whole assembly as 1 piece, but it is still a lot of labor to make the sandwitch, run it, then disassemble etc.
Edit, Limy Sami already described what I also had in mind.

The flat conveyor with appropriatly articulated abrasive wheels or brushes from the top make much more sense, and productivity would be also much greater then vibratory tumbling.

Have you considered a different layout on your parent material that would leave two or more frames attached such that the parts would not interlock during tumbling? Something that would leave the parts attached in a bottom location where hand finishing a small area would clean up the attachment points in a satisfactory manner.

You want a supplier with something like a Steelmaster deburring machine. Here's a shop near you that can supply finished parts--> Vander-Bend Manufacturing

Toroidal vibratories are the best at parts separation, barrel tumblers the worst. So a barrel tumbler wouldn't help with your monkey puzzle problem unless there were only one part/barrel.

Misc thoughts: Have you tried a tub vibratory? JR's suggestion to get others involved is right, though AFAIK, Sweco doesn't get involved in specific applications. A tumbling house might be more useful. And, what happens with the monkey puzzle? Is that so bad? Possible to do most of the finishing that way in spite of the puzzle, then individualized attention to finish the little booboos?

Intriguing problem...

That is a fairly simple job. What you are looking for is a vibratory tub with dividers. Your holes have plenty of size to let the media get in there to do your work. That's good. You didn't say your production rate but the parts would be done in 15-30 minutes. So if you had a machine with 19 dividers you could get 40-80 parts per hour with one operator. Hopefully that will work for you. Rick Vibratory Finishing Mass Finishing Ball Burnishing Deburring Media Compound Equipment