5mm compression

[woodworx]

I have been using my 5mm compression from centurion to cut all my ecab parts for the past few months. I love the compression part of the bit but I am always getting chatter when I cut melamine. It leaves me with rough edges. I thought it might be the software, but after using the bit on normal toolpaths in AC I am finding I get the same results. I am even getting chatter when I slow my feed rate and when I switch cutting direction. I will try a 1/4 compression next run to see if my results improve.

NEED AIR DRILL!

[thewoodcrafter]

I think you will see a big improvement in the cut quality with a 1/4" bit. Big difference from a 5mm bit.

[benchmench]

Have you tried slowing the move speed and/or taking more passes?

[benchmench]

Sorry, I didn't read all of the post before posting! I'm using the Centurion 5mm and have slowed down (depending on material) to between 4 and 6 IPS with a 6mm pass depth.

[Gary Campbell]

Justin...
Even the most robust of air drills may have a problem with melamine due to the fact that the material dulls bits very quickly.

I have just set up a PRSstd in Nevis, W. I. with a drill. We have been cutting at 200ipm onionskin (.68 depth 1st pass) with a .25 mortise compression. Using a "not quite new" bit off the boring machine, 5mm holes were difficult to drill in melamine, particularly penetrating the surface. A new bit helped, but after a hundred or so holes were drilled (at 45ipm plunge) we experienced lost steps. slowing the plunge rate accelerated the bit heating, wear and plugging up the hole. There was no problem whatsoever with any plywood.

You might want to try your drilling with 5mm bit first, then change to .25 to cut outlines. The time saved in passes will make up for that lost with the toolchange. Most special purpose melamine bits have chipbreaker design, you might want to look into one of these for a test.
Gary

[woodworx]

Gary,
This is what I plan to do. I need to know what new custom files have to be created to allow me to change bits during the file. I would love to do a 3/8 compression, but then I will have to change bits 3 times per sheet. i.e. holes, dados, and profile cut outs.

[bleeth]

Justin:
I found the 5mm compression bits to be a bit tender. They did send me a couple replacements to try but I haven't done so yet. I use the downcutters and get 15-20 sheets with clean drilling and edges. With my PRT I am cutting 1.7/sec and doing three passes through. As long as my spoil board isn't heavily grooved I get pretty good, but not excellent backs. Since all exposed ends are post laminated the little bit of bottom chipping I get is not an issue.
I'll be stepping up the speed when the gantry rebuild is finally done (stop laughing guys).

[bleeth]

By the way-instead of air drill think about a small engraving spindle-less runout.

[daski]

We have two Z axis on a PRT with 4 G board. One is a spindle 12000 rpm cutting at 2.3 IPS in 2 rough passes and on final onion skin remover, using centurion 1/4" compression, great cuts for 20-30 sheets then throw out, max sheets was 96. The other head has a Hitachi paint mixing drill using CMT extreme solid carbide 5mm drill bit. It's not a typical boring bit and no one stocks them and they are twice the price BUT the drill bit has a very big down shear edge so no chips on the top surface. We drill thousands of holes, all perfect. If you haven't tried one you're missing out. If you want to try one email me, my supplier now stocks them.

[erniek]

I guess I must be lucky somehow. I've had my PRT for two yrs and it's still drilling clean 5mm holes with the original bit. My second Z axis is a bosch router with a two flute 5mm bit.
I remember back when I first started that the 5mm holes looked like the bit was overheating, blackened a bit, to them so I raised the plunge speed to 4 IPS and changed the ramping settings for the A axis to be more agressive and now no more burning.

[loriny]

Just a quick plug for centurion tools. They now have available 5mm mortise compression routers. I have ten on order and will try remember to post when I have received and tesetd them
Lorin

[bleeth]

I have started using Centurians 5mm compression bit and it is cutting like a champ. I would say that the first couple probably had a slightly different geometry. At this point the first one I used went through about 15 sheets of plywood with white laminate on one side before a slight amount of degradation on the edges of the dado's started. We initially got a bit of burning at the holes but changed the boring toolpath to peck back to zero once from straight drilling and that took care of that.

[thewoodcrafter]

How slow do you guys need to cut to use a 5mm bit?

You can't use a 1/4" bit?

I guess you are doing frameless?

[boubou]

I am using 5mm centurion compression bit with great results. The .625 melamine cuts perfectly on both sides, dados are right on and shelf holes are perfect. I run at 4 ips for dados (one pass), 5 ips for outlines (2 passes at .310,.620 and clean up pass at .655 and 3 ips for drilling. Spindle speed is 13,000 rpm, a bit will last 15 sheets with perfect cuts, after that the edges gets a little rough. Turnaround on a sheet average 15 minutes, fast enough for a one man show. For melamine, a flat table with a good hold down vaccuum is a must, otherwise you will never get a good finish on your cuts. Ecab is amazing for fast and accurate cabinet production. Boubou

[bleeth]

Roger:
Since My Gantry is the older PRT style my speed cutting with any bit is somewhat restricted. I cut at 1.75/sec and use a last pass tolerance. Our most used material is 3/4 ply with whie VG lam or liner on one side.
Theoretically though this is the weekend for the rebuild. Then I'll be running a series of tests. With the Gecko and PRT motors I should then be cutting around 4-6 ips. I jog at 10. I know some others cut with similar setups faster but I find I lose accuracy by pushing it more.
I have an air drill in the "attic" and once it is installed I'll be able to cut with a 1/4".
Yep-all frameless and system screws for slides and hinges. When I first started doing the commercial boxes I used a 1/4" for everything and made the screw holes oversize to bang in an insert-what a pain that was. When Fred made his 5mm bit I was first in line.

[loriny]

The new one is a Mortise compression. I too have been using the compression router for some time. I made a mistake on my order though and will be receiving standard compressions again.
Lorin