End Mill Holder vs ER Collet Chuck

[CNCheese]

Can you use an ER25 collet chuck to hold a 1/2 inch solid carbide end mill?

I'm trying to put together tooling for new cnc machines we purchased, VMC and Lathe. All the in house experience we have is with manual machines, DRO on some. My personal experience is 0, unless you count the 2 years of metal shop in high school, many years ago.

Reason I ask is that the advice I've been getting from the veterans in the shop is that is alright to use a collet chuck instead of an end mill holder. What's the difference? I mean if one will work then why have the other?

thanks...

[Gabe Newell]

I use er-32 collet chucks to machine d2.

I have end mill holders but don't use them.

I've started using shrink fit holders and vastly prefer them to either collet chucks or end mill holders.

In theory collet chucks have advantages in finishing and end mill holders in roughing (see cnccookbook.com for a discussion of this and pointers to the reference research).

If I had to pick one or the other it would be collet chucks. None of my end mills have wheldon shanks anymore.

[CNCheese]

I also order a couple of the ER32 holders as well, thanks for confirming.

You're using shrink fit? Are you freezing the tool or heating the holder?

Thanks again!

[rowbare]

Here is video that shows how shrink fit works:

[nomedia="http://www.youtube.com/watch?v=ONaJvU801Ew"]YouTube- How Shrink Fit Works - Shrink Fit Machine Shrink Fit Toolholder Tutorial[/nomedia]

bob

[Geof]

Can you use an ER25 collet chuck to hold a 1/2 inch solid carbide end mill?......

Yes but it depends on what you want the end mill to do. As mentioned above end mill holders where the setscrew engages with a flat on the weldon shank may be preferred for roughing while collet holders are fine for finishing. I have found that collet holders can work quite well for both provided the nut is torqued up fully. By fully I mean an unbelievable amount; my memory which is not always reliable tells me an ER32 collet holder can be torqued to something like 80lbft but how you can do this with the dinky little wrench that is used is beyond me.

I have found with high helix endmills taking heavy cuts it is possible to gradually pull an endmill out of a collet holder but this is when it is really working, radial engagement around 60% of diameter, axial 150% of diameter, feed 0.005" per tooth but for more conservative machining they can be fine.

A caveat I do have, however, is that in my experience sometimes a cutter will be more prone to chatter in a collet holder.

[CNCheese]

rowbare - Great link! tks

Geof - Thanks for the insight. For now were going extremely conservative. Plan is to simulate in esprit, dry run, cut wax and then make chips, I'm crash paranoid. ROT for now is max cuts of 1/4" tool diameter (radial) and 3/4" flute height (axial) when using collet holders. Think that will work? We may get more aggressive with a weldon style holders down the road.

We drank the koolaid and went with Hurco TM10 and VM20 w/ 10" rotary, also purchased esprit with mill pro option. Hope this combination of conversational and CAM will get us up and running asap.

[Gabe Newell]

For er-32 I use an er torque wrench set to 80-90% of 125 lb/ft (factory recommendation for my collets).

A useful overview of different tool holding methods on a bunch of different parameters is on page 3 of this doc

http://parlec.com/downloads/parlec_w...ction_2008.pdf

[CNCheese]

Gabe - Thanks for the link, Parlec has a good looking catalog with great info, it's now in the reference folder. How's their quality? I'm trying to buy USA as much as possible. Do you know if CNCZone has a preferred vendor listing?

[Gabe Newell]

I have several Parlec shrink fit holders and they've been fine. My main issue with them is they are hard to read because of the finish they put on their holders (dark gray satin and they just use part numbers rather than descriptions).

New shrink fit holders show up on ebay quite a bit in the $70-$80 range. Used ones typically go for $30. I wouldn't buy other used tool holders on ebay, but shrink fit holders are simple and robust enough. I haven't had a problem with any I've bought that way. Right now there are a couple of Cat-40 holders up, both Kennametal.

[BobWarfield]

As has been mentioned, properly torquing the ER holders is key!

Another thought. The advantage of the collet chucks for finishing is less runout. Runout is a real issue as your cutter gets smaller. Think of the max allowable runout in terms of a % of the cutter's diameter. A 1/16" endmill can tolerate about 1/8 as much runnout as a 1/2" endmill.

In my shop, I only use collet chucks for cutters less than 1/2" in diameter for that reason.

FWIW, great deals on collet chucks available at Glacern and Maritool. Probably others too, but I have experience with those.

Cheers,

BW

[CNCheese]

Shrink Fitting will have to wait until we get some paying jobs through the door. Our shop primarily maintains tool and die sets for the production dept. Our plan is parallel introduction of the CNC machine tools into the current machining system already in place. After we get hooked on them and gain more experienced we'll start trying to pick up outside machine work.

It's all new to me though... Sadly, the only thing I'm bringing to the table is a bit knowledge of computers/programming and determination. Everything else about machining I'm having to learn on my own, hence my serious appreciation for all the responses.

Thanks again for all the help!

[Gabe Newell]

I also came to machining from software.

Haas Super Mini Mill 2 (similar to your Hurco with a slightly smaller work area and 5 less HP)

Solidworks for modeling
HSMWorks for CAM

Techniks shrink fit unit
Lakeshore Carbide for tools
eBay for shrink fit holders

Blasocut 4000 for coolant

Bob's GWizard tool is extremely useful. It not only gives you answers but also let's you explore choices.