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Leadhead
02-10-2013, 09:31 AM
Metal man, not at all used to cutting ply/MDF. But need to cut some fairly complicated profiles.
Could anyone generalise on cutter types and speeds/feeds for me please.
Need to cut 12mm ply profiles and MDF in 3D.
Have normal metal 2/3/4F HSS & Carbide. My best results in ply seem to be 5-10 mm dia. 3F Carbide. But still tearing the laminations a little. (Is there a technique perhaps? Climb milling?) or would I be better to buy dedicated router type bits for this??
Getting expensive experimenting!

~andy
02-10-2013, 11:22 AM
Have normal metal 2/3/4F HSS & Carbide. My best results in ply seem to be 5-10 mm dia. 3F Carbide. But still tearing the laminations a little. (Is there a technique perhaps? Climb milling?) or would I be better to buy dedicated router type bits for this??
Getting expensive experimenting!

I mainly work with hardwoods, but I would suggest you try a 5-10mm straight twin flute designed for wood.

TCT if you want if you want it to last. Personally I recommend Trend brand bits for wood, but you never spend much less than 20 a bit, sadly.

JAZZCNC
02-10-2013, 11:47 AM
For general cutting of MDF the 2F carbide metal cutters are fine but if you want to cut laminates or plywood then you need carbide spiral flute downward cutters.
Down cutters do exactly that they push down so don't pull the laminate edge, they are also good for thin material or wide material where you can't clamp or hold centre. IE No vacuum table. Only down side is they don't extract chips upwards so need either vacuum extraction or clearing slot with air.

Spiral Up cut give better finish but again do what they say and try to pull up on material, generally because they are spiral fluted they don't rip laminate but they can if poor laminate or blunt. They give good chip extraction has the chips are directed upwards so extract well and suit machines with no Vacuum extraction.

In general cutters designed for wood give a better finish and last longer than Milling cutters because there cutting edges are ground to different angles more suited for wood.

This place is good industrial quality wood cutters designed for CNC. . . Wealden Tool Company Limited Down Cut (http://www.wealdentool.com/acatalog/Online_Catalogue_Down_Cut_228.html)

Speeds and feeds will mostly depend on your machine and how strong and fast it is, also for 3D how well tuned motors are.? For cutting 3D then you'll probably want the motor tuning more biased towards acceleration has it will give shorter cycle times.!

For general MDF cutting then I'd start with 50% cutter Depth and between 14-20Krpm and 5mtr/min to 8mtr/min depending on cutter size. IE: 10mm cutter 5mm DOC 14K 5mtr/min and over end 6mm cutter 3mmDOC 20Krpm 8Mtr/min. . . . If you cut deeper then knock 10-20% off FR & RPM.
All this mostly depends on how stiff your machine is so you'll need to tweak from here but those figures I've give all work well on My DIY machine so they are realistic.

For 3D work then being honest with small step-over's and Low DOC required for good finish then I think your machine speed will be the limiting factor not the tool.!

Leadhead
02-10-2013, 02:59 PM
I was a bit suspect of my spindle speeds. As my machine came with a quill clamp to fit a router. I am now bushing my router out to suit and have purchased TCT 10mm S/Fl. cutter and ordered A Wealdon down cutter.
Thanks for info Gentlemen.