Any 'Got-ya's when Routing Laminated Particle Board?

[Sterob]

I'm making my a small benchtop router table and I bought a piece of 35mm thick Laminated benchtop to use for the top.
I thought I'd use my 9060 cnc Router to cut out for the Router Plate. ( 299 x 235mm? ).

I will only get one shot at this, so I was wondering if there is anything I should or shouldn't do when doing this?

Plan is to Machine a 10mm deep cutout for the plate and a smaller hole for the router to fit.

A Google saw mention of a Compression Spiral Router Bit, to prevent tear-out . Is that necessary or will other bits work ok? Is tear-out likely?

I was thinking of using a surfacing bit ( like below ), to cut out the plate section and just a 6mm 2 straight flute cutter for the cut out . Good idea or not?

Steve


Surfacing Bit.jpgpreview.jpg

[aldav]

I wouldn't be using a surfacing bit on plastic laminated chipboard. Yes, solid carbide spiral bits will work best, as you have a cnc it's surprising you don't have any, but a compression bit shouldn't be necessary for a one off job like this. Standard two flute mortising bits should work acceptably well.

[pippin88]

Only top surface finish matter rights?

Best would be a downcut spiral

[Lappa]

I would also go with spiral downcut. I have seen people cover the whole surface with tape first which they say prevents/lessens chipping.

[Sterob]

I wouldn't be using a surfacing bit on plastic laminated chipboard. Yes, solid carbide spiral bits will work best, as you have a cnc it's surprising you don't have any, but a compression bit shouldn't be necessary for a one off job like this. Standard two flute mortising bits should work acceptably well.

I have lots of 3 and 4 mm straight spiral bits but no compression or down cut bits. Have not needed any for what I do.

Maybe I'll order some 6mm compression spiral bits for this job.

[pippin88]

I would not use a compression bit for this

Compression bit has an upcut section at the tip anf then downcut
They are for optimising both surfaces. They need to be used at full thickness essentially

I would guess that you are routing a pocket for the plate to sit in (needs something to rest on) and then a through hole for the router.
A downcut bit is best for the pocket (where the top surface edge matters)

Compression bits are good for production use for sheet goods where doing full thickness cuts

[Sterob]

I would not use a compression bit for this

Compression bit has an upcut section at the tip anf then downcut
They are for optimising both surfaces. They need to be used at full thickness essentially

I would guess that you are routing a pocket for the plate to sit in (needs something to rest on) and then a through hole for the router.
A downcut bit is best for the pocket (where the top surface edge matters)

Compression bits are good for production use for sheet goods where doing full thickness cuts

Thanks Pippin. That makes sense.

[malb]

Agree with the arguments against a compression bit for the plate rebate. Used to operate a large industrial CNC router in a kitchen factory. Compression bits were our bread and butter bit for cutting out panels, but they did it in two passes. The first pass was offset from the final edge about 0.5mm, and ramped down at about a 10% slope to penetrate for each cutting path, leaving about 0.1mm of material thickness uncut. The second pass trimmed to final size and fully penetrated the sheet, leaving a neat edge with perfect top and bottom faces because the compression bit always pulls/pushes the face layers against the core, supporting the layers to prevent chipping. The offset ramp cut to penetrate the panel for the first cut can create minor surface layer chipping, but this is offset from the finishing path, and the cosmetic effect is eliminated in the second pass where the bit us then using the downcut spiral section for the upper face.

[Sterob]

Agree with the arguments against a compression bit for the plate rebate. Used to operate a large industrial CNC router in a kitchen factory. Compression bits were our bread and butter bit for cutting out panels, but they did it in two passes. The first pass was offset from the final edge about 0.5mm, and ramped down at about a 10% slope to penetrate for each cutting path, leaving about 0.1mm of material thickness uncut. The second pass trimmed to final size and fully penetrated the sheet, leaving a neat edge with perfect top and bottom faces because the compression bit always pulls/pushes the face layers against the core, supporting the layers to prevent chipping. The offset ramp cut to penetrate the panel for the first cut can create minor surface layer chipping, but this is offset from the finishing path, and the cosmetic effect is eliminated in the second pass where the bit us then using the downcut spiral section for the upper face.

So to summarise ( if I have got this right...)
Use a Compression Spiral bit when cutting all the way through a laminated part, ( in one pass?) so both top and bottom surfaces have reduced chipping?

Use a Down Cut Spiral Bit when cutting a rebate, as only the top surface needs to protected from chipping......correct?


So I can use Down Cut Bit to cut both sections as I am not concerned about the bottom layer?


lol

[pippin88]

Correct

[Sterob]

Thanks guys. Down cut bits on the way....