CNC cutting services?

[FunkyKikuchiyo]

I've been working on this first production run for WAAAAYY too long. I've hit snags, not least of which was a sickness/death in the family which kept me out of the workshop and kept me from accumulating necessary funds. It seems I'm down to my last obstacle, and it really has me stuck....

I was working with a CNC cutter to get some phenolic parts made for me; they were definitely beyond the abilities to make them by hand. I may have over-designed them, but that is beside the point. I have all of that set. It is a blade design, and I have CAD drawings for the blade as well, and it is a laminated core. I make the lamination sheets, and I've had a friend with a CNC cut out pieces for prototypes, but no one seems to want to cut these for me.

I've had a total of four people fall through on me for cutting these. One fell through because it turned out to be a plasma cutter which wouldn't work with the laminations (I think), another because the volume was too high, and two others are saying they'd love to have my business but just don't have their *$^# together enough to return phone calls. They require a BIT more work than a standard blade by nature of the press fit and the laminations, but I still could just invest in some tools (Harbor Freight?) and do it by hand. I thought I'd check here and see if anyone had a favorite go-to for such stuff and wanted to recommend them.

[defaced]

What cutting capabilities do you need? What kind of tolerances? What material(s)?

[David King]

Water jet or metal cutting laser would seem like obvious starting places. Are the laminations supposed to be insulated from each other? That could be a big liability in most cutting processes.

[FunkyKikuchiyo]

Metal cutting laser? Didn't realize there was such a thing.

Yeah, it is three pieces of steel laminated together with a paper/epoxy concoction. The total thickness is average .078". They need to stay insulated. I was assuming a normal mill style CNC was going to be the only option.

I need tolerances within a few thousandths, within a thousandth probably on one dimension for a press fit. I could do them by hand (really not any different than hand making acoustic saddles) but my first production run needs 150 of them, and that seems a bit tedious. I may just go with it, though... not many CNC folks really are interested in a production run of that size, but it is really all I can afford.

[defaced]

Yea, lasers are used alot for cutting metal. The biggest (?) laser shop in town is right around the corner from where I worked which is why I was asking for details. That said, I don't think you're going to get 0.001" out of a laser, and your insulation might go for a fiery ride.

[FunkyKikuchiyo]

Yea, lasers are used alot for cutting metal. The biggest (?) laser shop in town is right around the corner from where I worked which is why I was asking for details. That said, I don't think you're going to get 0.001" out of a laser, and your insulation might go for a fiery ride.

I figured as such. I was excited about a guy I know having a plasma cutter in his garage until I read about how they worked and realized it would probably go up in a puff of smoke with that, too.

I should probably say on the tolerances that is where they ultimately need to be - I'm not opposed to finishing it up by hand. I don't really know what is practical. Obviously with milling if it is a decent machine and the passes are slow enough, .001" isn't too bad, but no one trying to make money off of CNC cutting is going to want to spend that much time.

[David King]

Listen CNC cutting is going to be way too slow and finicky. I'd suggest you get a stamp made and stamp them out one-by one and laminate them after the fact. A stamping place can give you a quote since they may have an in-house tool and die shop or work closely with one. That way you'll be good to go for your first 150 and your next 1000 as well. A good water jet place can get you better than .005" but not .001. Laser should be better but the cost will be a lot higher. I'd try waterjet first and see how that works for you. They can pop some samples out for you in minutes if you have the artwork all ready to go. Those metal cutting lasers are so expensive you might just have to settle for one of the out of town, web-based specialty places.

You can read through this comparison Laser cutting vs. water jet cutting - standard metal cutting processes which is probably laser biased...

[David Schwab]

Another way to have them cut out with laser or water jet, etc, and then laminate them.

[FunkyKikuchiyo]

Yeah, I guess I'm exaggerating the tolerances a bit. .005" would probably be okay - I'd have to hand fit each one, but with that little material removal, it would be okay. .001"-.002" is my FINAL tolerance for a press fit I think, but not necessarily for coming off of the CNC.

I honestly don't see how I could laminate them individually, maintain thickness, keep them straight and not make a mess without it being a LOT of work. things like to skate around under clamps and I'd have edging to clean up, which would ultimately have to be trimmed within tolerances anyway... not to mention having to do one at a time when the epoxy takes 12 hours to set.

[David King]

FunkyK.
I think you are over-thinking this. Why glue the lams together? Why epoxy? Just stick them together with a double-sided mylar tape and stuff them in the bobbin which will hold them together.
If you have to use glue, just make a high density polypropylene jig to keep them aligned while the glue sets up. A thermo-set epoxy would speed it up, bake it for 30 minutes at 160 or whatever the formulation calls for. What you are trying to do sounds like old and well developed technology.

Just know that whatever you do to cut a laminated part is bound to put a lot of stress on the part -either thermal stress or mechanical stress and the things are very unlikely to hang together.

[David Schwab]

I agree about the double sided tape. I laminate some blades with that stuff. It sticks them together and acts as an insulator.

For all other pickup gluing I use CA.

[FunkyKikuchiyo]

Just know that whatever you do to cut a laminated part is bound to put a lot of stress on the part -either thermal stress or mechanical stress and the things are very unlikely to hang together.

I had extremely good success in prototyping with cutting it - in fact, the cutter used for that seemed to like cutting the laminated stuff more than solid stuff when I switched from solid blade to laminated.

I'm not opposed to rethinking the whole process (I'm seriously considering it right now), but I also prototyped the whole thing based on the given insulators - I did have issues with changing up thicknesses and changing the sound, and at this point I'm hesitant to throw all of that out the window.

How does the tape hold up over time? My fear is that pickups like to attract lots of dirt and grease on the tops and it could do weird things. I also had REALLY bad luck with superglue in the very first manifestation of a laminated blade. It hates soldering irons, for one.

I think I've created a method that needs tooling and development beyond my means - but I'm not yet convinced that it is bad or impractical in the long term.

[David King]

I was going to say that you could sit down with a jewelers saw and pump out quite a few of these in an hour if the shape isn't too complex. A few seconds of cleanup on a belt sander and you'd be on to the next.

[FunkyKikuchiyo]

I was going to say that you could sit down with a jewelers saw and pump out quite a few of these in an hour if the shape isn't too complex. A few seconds of cleanup on a belt sander and you'd be on to the next.

That is my plan B. I read a great tip on here from someone (I forget whom) that you can print out cad drawings onto avery stickers and make cutting/shaping really easy... just stick it on, and go to the lines. My printer seems to have some pretty good dimensional stability (surprisingly so, it is not a fancy one), and it seems like a good idea. What tools I'll invest in are another matter. I have the belt sander, but some sort of metal cutter, grinder/polisher, and possibly an oscillating drum sander would be on the wish list. Realistically it would pay for itself by not paying for CNC services, but I don't know how labor intensive it would be with affordable tooling.

[David King]

The best sander for this work is a little 1" x 42" belt from Rockwell. You see them on CL from time to time. You could also look for a Dewalt scroll saw if you want to speed things up (and blow some dough).