Bit recommendation

[diapowder2000]

Finally I have my first job order.
Cutting 13 letters(25Wx30H,inch) from 2inch
Ultraboard. Could anyone be kind enough to recommend me proper bit for the job? I'm kind of excited and of scared at the same time.
Thank you. Have a good weekend :-)

[gerald_d]

Chris, if the board is 2" thick then you will need a cutter of about 2.5" to 3" long. I am guessing that it will be 3/8" or thicker. Will this cutter diameter be okay for the definition needed on the letters?

[gamisano]

Chris,
onsrud has a foam bit 40-562 that has a cutting length of 3 5/8". I have used it on several foam applications including eps, and gator foam. On the laminated foam the bit tends to leave an edge on the top laminate layer since it is an upcut spiral bit. The edge can be easily sanded with some fine sandpaper, but can be time consuming if doing a bunch of letters. You might try to find another bit that is compatible with foam yet doesn't have the upcut. Perhaps and o-flute might work better. The main thing to look for, as Gerald mentioned, is to make sure you cutting edge length is longer than the material thickness. I tried cutting some 2" foam with a 1 1/2" bit, thinking that the shank could extend the extra 1/2" into the already cut foam, but this made the foam melt to the shank....so, you need the cutting length to be longer than the thickness of the foam. Good luck.

Guido

[gerald_d]

I don't know "Ultraboard" and didn't realise there might be a plastic welding issue. Chris, couldn't you have picked an easier (thinner) first job?

[jhicks]

Chris, I'm not familiar with Ultraboard but these posts seem to indicate its like gator Foam but I think I've heard it may not route as well? Assuming it is, here is what we have learned on Gator Foam.
1) IF you have an MDF spoil board on your bot, you will need to place something else on top of it/below the gator foam before cutting. The reason is; When you cut through, your bit will need to go ALL the way through and into the spoil board slightly to deliver crisp edges on the bottom material "skin". This will kick up MDF dust and leave a nasty brown dust on those pretty white edges and ruin your letters. We use one or 2 sheets of Vacuum form plastic sheet about .030 thick below the Gator foam to prevent this. Your foam supplier can probably provide this. Ours sends us free sample sheets with the foam order but its cheap if you need to buy it.
2) The bit we like best is an O-Flute. In spite of the fact Onsrud has a "Foam cutter bit", when you see the cut it delivers and discuss with them, they direct you to an O-Flute and the edge is much cleaner at least with the 1/4" and 1/8" bits we use.
3) Use a conventional cut direction for the cleanest edge, climb cuts leave a rough edge.
4) We have cut 2", 1.5" and 1/2" and always find the O-Flute does the best.
5) To cut the foam bottom "skin" completely through (or the skin it leaves may break inside the cut/letter area on the bottom when you remove it), we set up the cut files with a 1/4" upcut spiral O-Flute 16,000 RPM at a 90"/min move speed, conventional cut, and nest the letters with 1.0" between vectors with a 1/4" O-Flute and an outside profile to leave .5" scrap between letters to hold the sheet together.
(Your speed and feed may need to be diffetent at this depth, call Onsrud for recommendations, good guys)
6)Set the material cut thickness to approximately .020" deeper than the actual material thickness to make sure the final pass cuts completely through the bottom gator foam skin (but not through the white plastic protective sheet below the foam or into the MDF spoil board).
7)drive the cut pattern with NO ramping on the 1st pass to .130" or .150" above the total material cut thickness, then use the final 2nd pass at the remaining .130 to .150" to cut the letters out.(Don't forget we're going .020 deeper than the actual material thickness)This leaves the "onion skin" of .130" holding the letters in place. That last /2nd pass has a low torque, gentle final cut out and the letters don't move during the final pass cut even without any vacuum or other hold downs for the letters.( on some letters we turn off the dust collection to prevent the center of B's or R's from being sucked up or interfering with a cut)
Of course if you have a vacuum set up you may be better cutting in 1 pass but we screw down the sheet with a predrilled pattern between letters (about 9 screws per sheet 3x3 to flatten/secure it on the table then re zero the Z).
8) We usually move the "start position" on each letter to a nice straight line area rather than the corners which is where they generally are in the original art files and try to place them in a fairly orderly positions and close proximity to one another to make the most efficient move from one to the next.(This also prevents abrupt final pass cuts from stopping on a corner with little skin holding it and the divots that can bust up a sharp corner)
9) Make sure letters like O's and D's with interior and exterior cuts start on the inside so you don't find yourself cutting the outside and have no holding area when it goes inside the O for example. Preview should show this but generally the cuts start on the inside of these letters. I'm just not sure if thats the case every time so we double check.
10) With a thick material and such a long bit, you will need to mimimize the "safe Z" above the material between moves so it doesn't go too high and rack the Z between letters. Do the math to be sure but we use .250 as a standard and less is better for best efficiency.(Again, a dust collector on this thick material could draw up the center but not have room to get OUT from under the collector skirt and cause some real problems)
11) Finally, before going into these production parts, we lay out the nested sheet so we can run at least 1 or 2 test cuts in the excess areas. With large letters there is generally not a lot of excess on a sheet for a REDO so it a bit touchy when you run the 1st file knowing there is little or no room for mistakes.If necessary try any size you can fit in the excess with the representative letters, T's, O's, A's etc just to see how it runs.
Thats my input but as always, your files and needs probably are unique so TEST any new method before committing to that entire sheet and production files.
Hope this helps and best of luck.
Bot On

[Brady Watson]

Chris,
Right from the horse's mouth (http://www.ultraboard.com/ultraboard_tech.html) :

"Routing of ULTRA BOARD works well for creating irregular shapes. We recommend bits available from Onsrud Cutter, Inc., (847) 362-1560 and Vanguard Tool Corp. (540) 673-3496. Use Onsrud Cutter series 52-200 or Vanguard Tool part number VSC-102. Router bits should be double fluted carbide, upward chip removal, with a 1/4” shank diameter and a 3/16” cutting diameter. For best results run at 18,000 rpm and 85 inches/minute. Feed rate may be varied to compensate for larger bit diameter and different rpm. For special and long router bits for CNC routers, we recommend contacting Hartlauer Bits (541) 343-0390."

Personally, I don't like spending a premium for what the metalworking industry calls an end mill. I would use a 2 flute 1/2" end mill with 3" length of cut (2" if I thought I could get away with it as the deflection of the bit will be less and chatter as well). I bought mine for about $60...solid carbide. Since most of them are 6" in length, you may have to cut an inch off of the shank. I did this by scoring the bit near the top, down 1" getting it nice and hot with a grinder...then just hit it with a squirt bottle filled with water. The bit will break right at the score cleanly.

-B

[diapowder2000]

Thank you Guido & GD.
Yeah, I wish I could but ces't la vie, no?
Sometime it happens as you wish & sometime not.
Have a good weekend :-)

[diapowder2000]

Thank you so much Jerry & Brady.
This novice is overwhelmed.
Have a good weekend :-)

[jhicks]

Whatever you find works best, please post the recommended methods and results. I need to check out the ULTRABOARD but will await your findings.

[jhicks]

Just re read and caution on 2 flute vs one but have no experience with ULTRABOARD so don't know for sure. all I can say is ONSRUD will be happy to discuss and sell you a 2 flute "Foam cutter" but after you own it, cut with it, and ask a few questions, they revert to an O-flute so BEWARE of initial recommendations and rely on the results you get. Knowing what I've seen and know now on foam, wood, and plastics, I feel the O-Flute is superior. Be safe and order both and test yourself before making the production run. Sooner or later you'll find the right use for both.
Bot ON.

[jhicks]

Just a post on some of the Gator Foam 2" thick letters after the vinyl was applied for colors and the customer finished the exhibit/booth.

4828

[mklafehn]

Jerry,

I'm a little confused on your step #7

7)drive the cut pattern with NO ramping on the 1st pass to .130" or .150" above the total material cut thickness, then use the final 2nd pass at the remaining .130 to .150" to cut the letters out.(Don't forget we're going .020 deeper than the actual material thickness)This leaves the "onion skin" of .130" holding the letters in place. That last /2nd pass has a low torque, gentle final cut out and the letters don't move during the final pass cut even without any vacuum or other hold downs for the letters.( on some letters we turn off the dust collection to prevent the center of B's or R's from being sucked up or interfering with a cut)

Can you clarify what exactly is happening. I know you want to cut all the way through the gator, but you mention an onion skin after the 2nd pass. Is there a 3rd pass. And what about the low torque. Are you using a spindle vs a router.

THX

[jhicks]

Mike, sorry about the poor explanation. I'll try to clarify. Material is 2.0" for this example.
Total cut file is 2 passes.

So in order to cut completely through, we set cut material depth to 2.020" and a final pass of .140" for this example.
Pass 1 goes to 1.880 (because we have set our bit paramater as max cut depth of 2.0" per pass 2.020"- 1.880" = .140 final pass)
This will leave an onion skin on a true 2.0" material of .120" but the 2nd pass will cut to the full 2.020 by cutting the remaining final pass at .140" or .020" into the clean plastic sheet below and leaves us a clean bottom edge and no MDF dust on the letters.

We use a spindle but I believe that even with a router, the thin final onion skin pass vs a full 1/4" or 3/4" deep cut on a final cut out, will reduce the torgue on the material and essentially trim out the parts thin bottom layer, rather than the force required to cut out the part moving against/through greater material mass.
We use this technique much as you might use a "bridge" or "Tabbing" to hold the pieces in place until the final "trimming" pass to cut it out.
With Tabbing we would need to cut the parts out manually and finish all those tab cuts. With an onion skin, the machine does the final work and the skin holds the part around its entire perimeter until the end of the cut. That's why we position "start points" on straight line sections rather than on sharp corners or curves.

Caution on hold downs so while this works for us all the time on wood, TRUPAN,Color Core, and foam, where we drill the material to the table outside the cut area, you may need to leave chips in the cut path, or turn off the dust collector until you see how it performs for your application.
Hope that is a better explanation.

[mklafehn]

Perfect!

[diapowder2000]

Good Monday morning, guys.
Thank you again Jerry for a kind explanation on
step #7, and thank you Mike for asking Jerry a
question that I would like to ask. But I just wonder if I can do all these steps with my PW1 and Porter router. Anyway, I have to call Onsrud distributors to buy bits. I was able to find O-Flute (#56-655, CED 1/2 CEL 21/8, OAL 6) and Foam Cutter(4-flute, upcut spiral, CED
1/2, CEL 35/8, OAL 6) from Onsrud catalog during
the weekend. Are they right choice ? Other spiral
O-flute bits are all shorter than 2.02" in CEL.
Did I miss something?
Brady, are you talking about Onsrud #52-367(CED 1/2, CEL 21/8, OAL 4) listed $67.65 ?

Jerry, I will post some photos and report when I
finish this job.
Wish me a luck & have a good day :-)

[elcruisr]

I've cut alot of ultraboard. Get the Onsrud foam cutter tool in whatever diameter you need for the job. I cut up to 2" with a 1/4" tool in two passes. Ultraboard has a website with good tech info that was quoted above. You can cut it with pretty much any tool but you won't get a clean edge unless you use a foam cutter tool. It will usually leave some tearout without the proper tool geometry. It's kind of finicky that way!

Eric