# Polypropylene Help



## NickStevensLV (Dec 12, 2014)

I am having a difficult time with going through bits at a rapid pace while routing single line files into polypropylene. I'm using 1/16 bit and going 3/32 deep on a Techno router. The first run the bit lasted 20 minutes and the second attempt the bit broke in 10 minutes. I set the speed to the suggested speed from the manufacturer. If anyone has any suggestions or tips i am all ears. 

Thanks for the help!!

Nick


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## Cherryville Chuck (Sep 28, 2010)

Welcome to the forum Nick. The general rule with handheld routers is to only go to a depth of about 1/2 the diameter at a time. Certainly no more than 1 diameter. I don't know if that applies to CNC cutting too.

In most cases like this I suggest that you try asking Onsrud's customer service. They are the most knowledgeable people I know of about feed speeds etc. If you google Onsrudcutter2010 (or Onsrud Cutter 2010 if the first one doesn't work) you should find them easily. One person I steered their direction tried their bits and said they were far superior to the top quality bit he had been using.


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## harrysin (Jan 15, 2007)

NickStevensLV said:


> I am having a difficult time with going through bits at a rapid pace while routing single line files into polypropylene. I'm using 1/16 bit and going 3/32 deep on a Techno router. The first run the bit lasted 20 minutes and the second attempt the bit broke in 10 minutes. I set the speed to the suggested speed from the manufacturer. If anyone has any suggestions or tips i am all ears.
> 
> Thanks for the help!!
> 
> Nick


I don't know what it is that you're making but if I had to make lots, or even one 1/16" slot I would try a slotting saw, they come in various thicknesses but the one shown, taking into account the set of the teeth is about 1/16". The photo is of course a set-up to illustrate what I mean, hence the table opening is too narrow for the saw.


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## bgriggs (Nov 26, 2008)

When you work with plastic and small bits the reason most break is because the chips weld together and form a ball on the bit. This puts load on the bit and doesn't allow later chips to be ejected properly. 

Adjust your feed rate and speed until you are getting flakes instead of pellets coming off the bit. Pellet shaped chips got too hot and stick back together as they cool. 

Use compressed air or a flood coolant to help.

Bill


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## Herb Stoops (Aug 28, 2012)

Bill to the rescue.


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## whimsofchaz (Jun 6, 2013)

I agree with Bill slow down the cutting speed. Also some compressed air pointed at the bit will help the removal of chips and cool the material down.


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## NickStevensLV (Dec 12, 2014)

Thanks for the suggestions everyone!!


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