Cutting MDF

[jimmythethief]

I have purchaced a PRT96...and am waiting for it, but would like to know before I get it what the ideal bits and speeds are for cutting 3/4" MDF...I also need a good source for bits...I was thinking of just using end mills as they seem like they will do the job just as well, but for alot less cash...

Erik

[mrdovey]

I've been looking at end mills as well; but am concerned that the chip loading (end mills appear to be designed to remove less material per flute/cut than router bits) will lead to seriously reduced feed rates or tool breakage. I'll probably give 'em a try; but suspect that my best results will come from really sharp carbide router bits.

Comments from anyone who's already been up this learning curve would be most welcome!

[gerald_d]

Would suggest that you read all the corners of this Forum to find hundreds of words about bits. The Keyword Search (http://www.talkshopbot.com/forum/cgi-bin/discus/board-search.cgi) feature could help you too.

[bruce_clark]

Erik,

Just my $.02. USE CARBIDE! First off, you are feeding your router though material WAY faster than you ever would by hand.

Second, MDF is about the worst thing you can cut with a toolbit, so you really want a good SHARP cutter to start with and have something that will keep its "edge". HSS cutters generally start out sharper, but because of continious cutting AND the excess cutting and rubbing (plus cutting MDF to boot) they will loose their sharpness VERY fast.

Look at Onsrud's website and see what they recommend for MDF.

Good luck,

Bruce

[rgbrown@itexas.net]

I have been using "Her-Saf" Indexible router bits for about a year. They are not for everyone but I like them. I get more wear from the inserts than with any other bit I have ever used. And, the cost per part using Her-Saf bits has been lower than any other bits I have used. But bit profiles for the indexable bits is limited.

I hate MDF. But, at times I am required to make parts from it. It is dusty, nasty and about as abrasive as any product I have worked with with the exception of FRP. If a Her-Saf bit had the right profile for the parts I need to make, it would be my first choice.

http://www.hersaf.com/

[jimmythethief]

1/4" end mill with 1" cutting lenth and 4 flutes, solid carbide...$7.20...can they be good? Can they be bad? How to tell? What do you guys think?
http://www.endmilldiscount.com/html/tool_pages/xl4.htm

[gerald_d]

Nothing there tells me that they are solid carbide - they might be HSS (High Speed Steel). It would be a good cheap starting point for you - nobody will laugh at you for making that choice. If they do, send them to me.

[jimmythethief]

http://www.endmilldiscount.com/html/storefront.htm

This says they are carbide...but your right they don't give very much info...maybe Chinese?

[ron_cleaver]

I've been making cabinets for my garage and basement using 3/4" MDF. After trying some of the so-called carbide bits, I was disappointed. So then I bought some 3/8" diameter Freud straight cutting bits. After cutting ~20 sheets the first bit is still working like new.

But I also changed my approach to cutting the MDF. Now I cut at 1"/sec and make 3 passes to cut through the sheet, leaving tabs on the last cut. The edges need very little sanding afterwards.

[kerrazy]

I have been cutting signs out of MDF with great results.
I have been using solid carbide onsrud cutters of various sizes and not leaving tabs, as so much dust is generated it fills the voids quite easily.

Ensure that you do have some form of a dust skirt set up as the dust from the MDF is vary dangerous with long enough exposure.

I also ensure my shop air cleaner is on full blast.

The MDF is very easy to work with and gives a good clean edge with v-bit cutters.

Iwill post some pictures of items later in the week so you can see the capabilities.

Dale

[kerrazy]

Also, there is a manufacturer in the US that has an exterior grade MDF coming to market called Extirra, I recieved a sample and have left it outside all summer and it is holding up well. Great for signs maybe? Thay offer a 5 yer warrnaty on it as well.

Dale

[elcruisr]

Do yourself a favor and not sweat the tooling cost so much! We currently cut over 190 sheets of 3/4 MDF and 3/4 plywood a week on a 'bot. The current contract is for 12,000 parts. We've found cheap bits have short lives and don't deliver the goods as far as I'm concerned. I obviously don't have time to play games with my cuts. I do single passes at 2.3" per second and often faster. We use primaily Onsrud single flute 3/8" compression spirals with a shorter than normal upcut. Remember, the more flutes you have the slower you have to cut, in general. Yes, there are exceptions but this is a general rule of thumb. We get about 1 1/2 shifts out of a bit and resharpen 3 times before pitching it. They give acceptable edge finish and the customer is very happy. When you look at the price per part of the tooling it's actually pretty small. Just use a really good dust collection system with that MDF.

Eric