That must be one of the hardest things to machine. The sheet metal is going to flap all over the place. You cannot hold it down without a vacuum table, and even then it would still be difficult.
Go back to plasma.
Cheers
Roger
Hi Guys,
Could someone please help me. I’m rather new to cnc, and only have worked with wood .
I picked up what I believe is 24”x36” x .0179 zinc plated sheet metal at lowes. I wish to cut out
A deco pattern for wall art that would be normally cut with a plasma. My questions are
1) Can I use a 1/8” HSS 4 flute spiral end mill to cut out the sheet metal ?
2) If yes, how much material should I remove each pass and how fast should it move?
I’m cutting with a cnc router parts pro machine with 35 steppers and a 3hp PC router .
Thanks Lou
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That must be one of the hardest things to machine. The sheet metal is going to flap all over the place. You cannot hold it down without a vacuum table, and even then it would still be difficult.
Go back to plasma.
Cheers
Roger
If it`s only 0.4mm I think it`s just a piece of cake on a 4 flute HSS, on my experience I can even cut 1mm thick stainless steel sheet, by just using a 1/8 carbide bit single flute at feedrate 400 and plunge rate of 80 on 5 passes, sometimes 7 passes, depending on the sharpness of my installed tool bit, it gets dull in time after a couple of cuts, so in the beginning I make a CAM for 5 passes and for 7 passes, after 20 cuts I change the code for 7 passes to continue working and after a couple of cuts that`s the time I re sharpen hehe, sometimes laziness made me think further just to minimize the tool change make sure to have a sacrificial plywood to avoid accidentally scraping your CNC table and to easily clamp your holding tabs in place.
Hi KHOUJ
That fine for a little thing like you show, but OP is talking about 24" x 36"!
But I just had a great idea! Thick flat plywood or chip board, contact cement, glue the sheet metal down HARD and all over, then machine it to 2 mm deep.
Then dunk the whole thing in solvent to float the metal off.
Yeah - MESSY!
Cheers
Roger
I'm guessing your router is fixed at 20k rpms or so?
Get a 3/32" short 2 flute carbide end mill and cut full depth at 20k rpms and 10 ipm.
Your HSS bit will just burn up at router speeds.
Also using a "DownCut" milling cutter helps a lot on thin material.
I know these are listed for wood, but I've used similar here in the UK on steel before without any problems.
2 Flute Downcut Bit, 1/8 Dia, 1/2 Cut Length, 1/4 Shank, Whiteside RD1600
Nick.
Have to be carbide for sure at those spindle speeds. A tiny downcut cutter is not a bad idea. Even so, I would suggest buying several at the start as one or two are bound to get snapped while getting the conditions right.
Double-sided tape for thin sheet metal? Hum ... I have some reservations. But - experiment. Try using a press to really get the adhesion everywhere. The downcut spiral will help to maintain the bond, and is a good idea for this.
Depth - full depth, right through the sheet metal. If you try to do it in several layers you will get a lot of rubbing on the underside of the cutter, but at full depth you will be cutting with the side of the flute which will be a lot cooler.
Cheers
Roger
I've used contact cement with a small carbide bit on a router on 1.2mm gal sheeting before. The glue worked well, no solvent required, a bit of gentle persuasion lifted the metal off then just polish down the residue with paint thinners. Double sided tape seems a bit dubious to me, too, I think you may find small details being lifted unless it's particularly special tape.
Agreed on getting multiple cutters. Two to snap, two to burn through and one to finish the job
Can you post a bigger picture on you work? also you preferred dimensions of your drawing, there`s no autoCAM software that can route your drawing in 0.2mm steps, you need to cut the inside parts first before cutting the outside outline, let me code it for you if you want
Two to snap, two to burn through and one to finish the job
Sigh
Sob
One ends up with a good collection of 6 mm carbide shanks after a while...
Cheers
Roger
Hi Roger,
Thanks, as I was learning yesterday, I had an early visit from Santa!!!
Well at least from rudolf and his glowing red nose!!!!
😂 Up on the cnc roof I heard a chatter, and when I looked I was blinded by a super red glow!!! And with a puff of smoke my bit was toast !! Hahahaha
I had set my cnc to run at 200ipm and a depth cut of .005”. Needless to say the first bit snapped. So I slowed the feed to 60ipm and got a lot of it cut until that bit wore out. Same with second bit but it went faster due to the fact that the wd40 started soaking into the mdf that I spray glued the sheet toand swelled up causing the bit to dig in to deep.
I don’t think the bits I have can take a single pass cut.
"200IPM" that would of been good to see, what RPM was the Spindle running at??
Other posts said you will just burn up the cutters, WD40 is not a cutting fluid for cutting steel sheet like this, it won't help your cutters at all, try some better real cutting fluid and a max of 7000RPM and 10 IPM
Mactec54
Lol, ok, I did say I was learning !!!! Hahaha
It wasn’t much of a sight, only got a 1/4” before it snapped.
The slowest I can get with this router is 10000. My old router only had one speed so I used a speed control but I’ve been told not to use it with this one because of the variable speed controller on the new one doesn’t play well with it .
I’m assuming at 10ipm your saying I should try to do a full depth cut and use the side of the bit instead of the tip ?
Here’s a pic of the bits I’m using....
Thanks again