Best CNC for aluminum signs?

[Signed Out]

Looking into purchasing a CNC, primary use would be aluminum (040, 063, 080) and dibond signs. A mix of runs, sometimes 2,000 8"x4" signs, and also smaller runs of signs. All signs would be printed vinyl/laminate mounted to the substrate before being cut down on the CNC. From my research, cutting aluminum with vinyl already applied can be tricky, and most likely have to use a mister, sometimes people prefer to put the vinyl side down when cutting on CNC?

Anyway, trying to decide which table to go for. I Don't think we need a conveyor system. I would like to not spend over 50k, want at least an 8'x4' table, but should probably just get a 5'x10'. I want the table to be efficient, so will need a camera or registration system. Vacuum hold down and tool changer. Perhaps I could add the tool changer down the road. I'd prefer to buy new, but realize might not be the best choice with my budget. I have been looking at colex, axyz, multicam and a few others.

So any recommendations or advice? Keep in mind CNC would be mostly used for cutting aluminum signs, ACM signs.

 

[Scotchbrite]

My only experience with CNC is the MultiCam machine we bought 21 years ago. Obviously it has held up well. We wish we had bought the larger 5'x10' size; I'd say do it if you have the room. From what I remember, the cost difference wasn't that much for the larger table size.

I also don't think you need a tool changer for what you're doing. We don't have one, and it's never bothered me. I don't think you really need one unless you're doing 3D type cutting with HDU.

I tend to apply the vinyl after cutting. I'm just too concerned about the edges of the vinyl getting lifted, especially at the corners. We've had success cutting with vinyl already applied, but we've only tried a couple of times. But we're also not doing batches of 2000 like you mentioned. I know with our machine, cutting them with the vinyl down would be a bad idea. If the cut isn't quite all the way thru, you may have some trouble dressing up the edges after the fact. Also a lot of times there's a little round piece from the bottom of the bit where it plunges in to start the cut and that little piece can get pushed under the material.

Bear in mind my experience is with 21 year old technology, so the newer stuff may not have as many issues. Heck we're still running one of the original versions of EnRoute. Lord help us if that Windows XP computer ever dies......

 

[Signed Out]

Also could someone shed some light on this too. When doing 8"x4" signs from a 8'x4' sheet of aluminum using our current setup (shear/punch press rounder and hole punch) we yield 144 signs per sheet, with zero wasted aluminum. What would be the max for a CNC? Tool width, plus you need to leave some material between pieces, right, and on the perimeter of the aluminum? Would I be looking more like 110-120 pieces per sheet? Also any insight to the cutting time per sheet?

 

[Signed Out]

My only experience with CNC is the MultiCam machine we bought 21 years ago. Obviously it has held up well. We wish we had bought the larger 5'x10' size; I'd say do it if you have the room. From what I remember, the cost difference wasn't that much for the larger table size.

I also don't think you need a tool changer for what you're doing. We don't have one, and it's never bothered me. I don't think you really need one unless you're doing 3D type cutting with HDU.

I tend to apply the vinyl after cutting. I'm just too concerned about the edges of the vinyl getting lifted, especially at the corners. We've had success cutting with vinyl already applied, but we've only tried a couple of times. But we're also not doing batches of 2000 like you mentioned. I know with our machine, cutting them with the vinyl down would be a bad idea. If the cut isn't quite all the way thru, you may have some trouble dressing up the edges after the fact. Also a lot of times there's a little round piece from the bottom of the bit where it plunges in to start the cut and that little piece can get pushed under the material.

Bear in mind my experience is with 21 year old technology, so the newer stuff may not have as many issues. Heck we're still running one of the original versions of EnRoute. Lord help us if that Windows XP computer ever dies......

On the tool changer, if all the signs have 4 holes in them, would you want to use the same bit for the holes? I assume you would cut out all the holes before cutting the perimeter.

 

[Scotchbrite]

Yes, sometimes the bit size I use for a job is dictated by a hole size. Usually were cutting stuff that needs at least a 1/4" hole and that's the largest diameter bit we're typically using. I like to use the 1/4" bit to get the best cut speed.

You are definitely going to lose the width of the bit between each piece. You can hug the margins a little tighter; it really depends on how square the material is. At the margins you need enough material to make sure you get a square cut.

So I would safely say you could get 121 of the 4"x8" out of a 4'x8' sheet. I'm doing the math by calling the size 4-1/4"x8-1/4". Think of your cuts being a grid versus being a bunch of rectangles.

 

[Scotchbrite]

Forgot to mention like JBurton said, when possible you can downsize your blank size to account for the loss from the bit diameter. I know it's a lot easier to make that work for an 18"x24" blank being downsized to 17-7/8"x23-7/8" versus a 4"x8" getting downsized by 1/8".

 

[Signed Out]

I got a ShopSabre IS612 with a camera and I'm loving it. Only problem is the camera workflow is not very intuitive, but the results are great. Problems with printing something with marks for the camera, then mounting to aluminum and cutting are 'easy' to work around. (That being said, 5 extra minutes a sheet in some setups means your printer is outrunning you router, doing politcal coro or something like that would not flow very well unless the folks at optiscout can simplify the process a bit. 5 extra minutes on a $500 prepped sheet is a different situation and is nothing to sweat)
For one, ACM works much better for this since you can run a downcut bit and no lubricant, keeping the edges of the material from lifting and from having oil introduced, potentially causing the print to fail at the cut edge. If it has to be aluminum, mount the print, run the camera initially so that the program will actually drill the marks through the sheet. Cover the holes with black vinyl, then flip the sheet. Now with your mirrored artwork, you can run the camera again and read the marks through the holes.
You would also want to be running alcohol as a lubricant/coolant rather than actual cutting lubricant, which has worked well in the past, it just gets expensive and is hazardous (I haven't seen anybody concerned with converting alcohol into a near vapor with the mister systems, but with my initial testing I attempted to ignite the mister of alcohol with a lighter, too much airflow kept it from igniting, but the whole idea had me nervous from the get go so we switched back) In theory you could step through your aluminum until you have foil left, then not use a mister on your final pass. The other downside to cutting with vinyl face down, especially on acm, if you have anything on the table, the vacuum will pull the material down with so much force it will dent your vinyl. I've even had it seperate some vinyl from the material where some lettering was cut into the MDF table.
Obviously cutting with a bit generates waste, but I can tell you an 1/8" bit will cut 1/4" aluminum just fine, so on a 4'x8' sheet, I could fit about 126 4"x8"(You can actually gang you parts edges together to reduce loss and cutting time, depending on the parts you're making). Or you could sell the parts at 'discounted' rate given a +/- .125" dimension and just ignore the tool offset and still get about 144 out of the sheet. You will run into issues with some parts totally flying free towards the end of the sheet, You can remedy this on some things by mounting premask to the side of the aluminum on the table, then not cutting through the premask. This also requires a very level table. Alternatively you can make jigs for common cuts like this, that would have grooves where the toolpath is, filled with paint, so that there is no loss of suction over the course of the sheet.
Tool changer is really really really handy. Don't skimp on that. You will want different bits for acm, acrylic/polycarbonate, aluminum, as well as different diameters and V bits. On my old machine I had to manually change the bits, and nobody else could really manage to get the collet to break free after I torqued it down, so literally every broken bit I had to change. Then reset the depth. On my new one, to change a bit (not broken bits) I hit a button, it grabs a new tool, and it knows where that tool is sitting in relation to the work piece.
We opted for a 6x12 table, I think with all the bells it came to under 90k, including the 10k 25hp vacuum setup. You could swing a 4x8 under that, depending on options.

The shop sabre, does it come with the camera or is that an add-on? Website is kind of vague, but the pricing looks intriguing.

 

[ProColorGraphics]

I know a lot of people like Colex. The samples I got, they show cutting through 3mm and 6mm aluminum without any issues.

 

[letterworks]

I'm guessing the reason to do this via cnc is the pre-printed part?

It would seem a laser line, a shear, and a corner punch would be wayyyyy better than figuring out hold down on thin aluminum on such small parts. You'll have to premask everything as the vinyl cut bits will stick to the part faces otherwise, and you'll probably need a 10-20K vacuum to get consistent results.

I say this as someone who has routed parts the size of a dime on a CNC....4"x8" size is horrible. Too large to want to prep each sheet properly and too small for things to "just work" consistently. A kick ass vac pump might fix it, with a downshear bit. But if you can shear it it's not clear to me why you would not continue to shear it.

 

[Signed Out]

I'm guessing the reason to do this via cnc is the pre-printed part?

It would seem a laser line, a shear, and a corner punch would be wayyyyy better than figuring out hold down on thin aluminum on such small parts. You'll have to premask everything as the vinyl cut bits will stick to the part faces otherwise, and you'll probably need a 10-20K vacuum to get consistent results.

I say this as someone who has routed parts the size of a dime on a CNC....4"x8" size is horrible. Too large to want to prep each sheet properly and too small for things to "just work" consistently. A kick *** vac pump might fix it, with a downshear bit. But if you can shear it it's not clear to me why you would not continue to shear it.

It's not so much the shearing part that's a drag for us, that goes quick. It's the holes and rounded corners. I've been having this debate with myself for years now. On these 2,000 sign runs, each sign gets 4 holes and 4 corners rounded, that's 16,000 punches. We do have a decent setup, air powered punch for rounding and hole punching. But it still sucks for the person doing it. I've gotten a quote for a combo corner/hole punch tool for $2,800, but it's only good for 1 corner/holes size/location combo.

I would love to find an automated punch press with a feeder that spins the piece stuffs it in the corner for you. Or maybe there's a desktop CNC with sheet feed setup out there that I could feed the sheared down signs for corners and holes?

I have always wanted to bring a CNC in house to for other opportunities too. Subbing out that stuff, I don't push the work so there is definitely some opportunity.

 

[ikarasu]

You need to consider time too. Cutting 121 4"x8" with holes on a CNC you're probably looking at 2ish hours a sheet. With prep and all. 8" is so small so you're also looking at double sided taping them to the spoil board, or using tabs. No way you cut them without as half will move and get messed up.

A sheer is way faster for something like this, even if you have to drill holes and corner punch them.

 

[Signed Out]

So currently it takes us about 40 hrs of labor to complete an order, including mounting prints to 8'x4' sheets with flatbed table, probably only 3 hrs there. So pretty close time wise. I hear what you're saying about the pieces moving around after they are cut. I wonder if it would be possible to setup so the CNC does the holes, and rounds the corners, but doesn't cut the horizontal straights, but cuts the vertical straights.. so the sheet stays all together, then bring over to the shear and finish off the cuts? Would probably have to space the pieces out a bit because the shear doesn't remove material like the router would... I know this would end up being difficult to line up the router cut edges with the sheared edge.

This is my struggle, our setup works, and is quick enough, but nobody likes to do it.

 

[Scotchbrite]

Never thought of a jig to "focus" vacuum JBurton that's a cool idea.

 

[Signed Out]

So for running all 4 sides of 4"x8" pieces 121 times, I come up with 37 minutes, for same count but not redundantly cutting the edges, 21 minutes. That's at 95 ipm, figuring on .040", no holes, no round corners. Give me a drawing with holes and such and I'll tell you better.
You can get aluminum with pvc already applied (thicker than the clear film that prepainted has on it) that is not much more expensive than standard sheeting, maybe $5 a sheet if I recall correctly.
View attachment 157492 View attachment 157493

With a 10k vacuum, you just need to sort the cuts so that you can port off areas of the table as they are completed, or throw a sheet of paper over the first half of the panels as the second half starts. Or if these are consistently produced runs, build jigs for each setup. The jig will have vacuum hold down where the finished parts are on the table and troughs where the tool will pass that are sealed, so no airflow is lost over the course of the program. Like these:

This is great thanks. Attached a copy of a single sign and our current print file. I was thinking something similar for a jig that lets the finished pieces "fall" into it's spot after it's finished cutting, what you described makes sense. What if you were to double up your vacuum supply and had enough holes so every piece is getting good suction, combined with zoning off areas that aren't being used?

 

[Signed Out]

How many would that be, how many holes, and cut out of what material? I could give you a very accurate estimate for production time on a fancy-ish CNC.

Easily, only problem is you'd need to shear the 1/8" that the tool would have taken off either side of the parts.

That's for 2,000 8"x4"x.040" aluminum. orajet 3551/ 290 laminate mounted to aluminum before cutting. Each sign gets (4) .5" radius corners and (4) 3/8" holes, total of 8,000 corners and 8,000 holes. Takes us about 40 hrs to mount prints to substrate, shear down, punch holes, round corners. We also stack and package as we go so that is probably about 6 hrs included in the 40.

 

[Scotchbrite]

For what it's worth, we've always used LDF for a spoil board on our CNC. It's kind of hard to find though and when you call around you have to emphasize LDF because they all assume you mean MDF.

 

[johnnysigns]

For $50k budget I think Shopsabre is the way to go. The camera setup on our Axyz is a little slow sometimes to read all the dots and it's quite sensitive to the lighting conditions, but I'd think printing registration dots and then cutting by camera would be smart. Also I don't think I'd get a machine w/out tool changing capabilities. It's a small add on, but even if you kept several diameter drill tools and your primary cutting tool in there with just a 4 tool ATC it would speed things up.

 

[Raum Divarco]

If your projects are heavy duty an old saber, Laguna tools, AXYZ or Multicam are probably all safe bets.
Everything else, even the colex, is a digital cutter and if you are trying to be highly productive you'll want more of a cnc router priority machine.

 

[Scotchbrite]

Speaking of, I recently learned they make HDO in addition to MDO, typically used for concrete forms. I never could find LDF locally, and didn't want to spin the wheel of chance on getting sheets delivered. What sort of shop did you locate some at?

The last time we got some was from a national lumber supply company

 

[letterworks]

Never thought of a jig to "focus" vacuum JBurton that's a cool idea.

It's more focusing the air flow capacity of the higher pressure pumps. They can't handle letting the air out in the not-important areas. The thicker MDF machine top is the same idea and I agree it's not intuitive. I never used pegboard but did use sintra with 1000's of smaller holes. That actually worked ok, and was good for dimensional stability and was better to tape things down to, but MDF is easier to replace and generally works better.

Note the same principal is why you see routers with strips of sintra and small vac holes made wider at the top surface. Limits airflow but gives more surface are for the pressure difference to hold.