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Heat shrink holder temperature

Pattnmaker

Stainless
Joined
Nov 2, 2007
Location
Hamilton, Ontario
How hot do heat shrink toolholders have to be heated for tool changing? I just ordered a couple of holders for roughing in aluminum. I have a small induction heater for forging that I can use for heating the holders but I don't want to overheat them. I roughed out an aluminum matchplate last week and had the 1/2" endmill push in about .005" while roughing using an ER32 collet.

Luckily it didn't pull out so when I used the same cutter for my horizontal toolpaths I just had to recut them after resetting them. I thought I had better get some more secure tool holders for roughing. I am leering of buying sidelocks for this machine as it has a 24000 rpm spindle.
 
There is more to heat shrink holders than just heating them up. The speed of heating is important too. Heat them too slow and the tool will grow also, maybe at a slower rate though. I have been having this conversation with Haimer over the last week or two. If you heat them to the wrong temp, you will destroy the temper and ruin them. I have done them with a heat gun years back but it was iffy if not done right. Never found a method that worked properly every time.

Paul
 
I use Maritool's induction machine. I run it while tugging on the dead cutter with pliers until it slips out, then pop in the new cutter and hit the stop button. I put a shaft collar on shank of the fresh cutter to precisely set the depth without worrying about stop screws.
 
If you use your induction coil for forging then I'd say it's probably way too much for shrinking holders, unless you exercise extreme caution.

I use a mapp torch with the holder in a turntable, has never given me any problems. It takes very little heat in reality, most of my shrink fit holders have barely any discolouration - the only ones that do are much heavier wall thickness.
 
How hot do heat shrink toolholders have to be heated for tool changing? I just ordered a couple of holders for roughing in aluminum. I have a small induction heater for forging that I can use for heating the holders but I don't want to overheat them. I roughed out an aluminum matchplate last week and had the 1/2" endmill push in about .005" while roughing using an ER32 collet.

Luckily it didn't pull out so when I used the same cutter for my horizontal toolpaths I just had to recut them after resetting them. I thought I had better get some more secure tool holders for roughing. I am leering of buying sidelocks for this machine as it has a 24000 rpm spindle.

If you are using heat shrink holders you really need to use the oem machine for those holders or perhaps another heating machine that can replicate the specs you need to have. You can get 1K+ cycles from a holder but reduce that number to 1 cycle if you overheat it. From the tool moving in the holder you may have done that already or perhaps you're using a cutter that isn't cnc qualified for heat shrink holders. In aluminum the only way you could move the tool is by an epic, really hard, pile drive crash that is YouTube worthy. And trying to guess the correct temperature is like guessing which vegetable oil to run in your shiny new Ford super duty. Don't do it.

I wouldn't use side locks at 24K rpm either. In fact we ditched all our solid side lock holders a while ago and use a lot of everything else, especially mill chucks and hydraulics. I think Schunk Tendo hydraulic holders are G2.5 @ 25K but don't quote me. We really like the Tendos; they're rigid, dampen great, have great runout and are a snap to set up a tool.
 
If you are using heat shrink holders you really need to use the oem machine for those holders or perhaps another heating machine that can replicate the specs you need to have. You can get 1K+ cycles from a holder but reduce that number to 1 cycle if you overheat it. From the tool moving in the holder you may have done that already or perhaps you're using a cutter that isn't cnc qualified for heat shrink holders. In aluminum the only way you could move the tool is by an epic, really hard, pile drive crash that is YouTube worthy. And trying to guess the correct temperature is like guessing which vegetable oil to run in your shiny new Ford super duty. Don't do it.

I wouldn't use side locks at 24K rpm either. In fact we ditched all our solid side lock holders a while ago and use a lot of everything else, especially mill chucks and hydraulics. I think Schunk Tendo hydraulic holders are G2.5 @ 25K but don't quote me. We really like the Tendos; they're rigid, dampen great, have great runout and are a snap to set up a tool.

I don't agree that it is an absolute must to use one of the dedicated machines. I'd agree that you'd be foolish not to if you're changing out more than a handful a day, because they are much faster and easier than messing around with other means. But if you're only doing one or two every other day then the mapp torch works perfectly well - as long as you heat evenly you're not ever going to overheat or otherwise damage the holder.

However, I would not use an induction coil designed for melting ingots or removing nuts or whatever else like that - all the ones I've seen are fairly dumb instruments with minimal controls and I think you would be far more liable to overheat a holder using one of those.

Also, for my purposes, I don't need to get a thousand cycles out of a holder. Shrink fit holders are inexpensive, and many times that I use them the tool that I shrink into it cost more than the holder. Even with basic end mills, a thousand cycles could easily amount to £50k+ of solid tools, you really need to stretch the £100 holder that far?
 
I can turn the induction heater down quite a bit and set a timer as well. I don't want to overheat it thus the question. I have already ordered 2 holders and they weren't horribly expensive so I am not going to pay a restocking fee to return them. Cutting aluminum I can't see changing tools very often. Unfortunately I often have to use a lot of long and extra long endmills which I suspect contributes to them moving. Any movement has been in ER25 or 32 collets not heat shrink tooling. Barely any discolouration sounds like only 500-600 degrees. I will test a similar section bar at the lowest setting to give me a baseline.

I meant to put this in the CNC section rather than CAD CAM.
 
I can turn the induction heater down quite a bit and set a timer as well. I don't want to overheat it thus the question. I have already ordered 2 holders and they weren't horribly expensive so I am not going to pay a restocking fee to return them. Cutting aluminum I can't see changing tools very often. Unfortunately I often have to use a lot of long and extra long endmills which I suspect contributes to them moving. Any movement has been in ER25 or 32 collets not heat shrink tooling. Barely any discolouration sounds like only 500-600 degrees. I will test a similar section bar at the lowest setting to give me a baseline.

I meant to put this in the CNC section rather than CAD CAM.

In that case I'm sure you can start low and try it out. When I'm putting tools in with the torch I just keep warming and offering the tool in until it falls in. It's a two man job the way I do it, but I am not doing it frequently so it doesn't matter. One man to rotate the holder, while I hold the torch and place the tool. Most of my shrink holders are in the 12mm range, and like you are primarily for reach and access. I have found they actually require very little heating, and those I have like that show practically no discoloration. The ones that require more heat and show some discoloration are all in the 20-25mm range.

If you measure the bore of your holders you will see that they are only a few thou smaller than nominal, doesn't take much to expand them that far.
 
I use a mapp torch with the holder in a turntable, has never given me any problems. It takes very little heat in reality, most of my shrink fit holders have barely any discolouration - the only ones that do are much heavier wall thickness.

Can you still get MAPP gas there? I used my last bottle a few years ago. It's all that MAP-Pro crap now which is barely hotter than propane.

I use a propane "crack torch" with a tool holder vise mounted on a turn table to shrink tools. I've had a couple guys complain about it, but personally I prefer the torch to an induction heater. Similar to gregor, the only tool holders with significant discoloration are the 3/4 holders. Takes about 90 seconds to swap a 1/2in tool.
 
Can you still get MAPP gas there? I used my last bottle a few years ago. It's all that MAP-Pro crap now which is barely hotter than propane.

I use a propane "crack torch" with a tool holder vise mounted on a turn table to shrink tools. I've had a couple guys complain about it, but personally I prefer the torch to an induction heater. Similar to gregor, the only tool holders with significant discoloration are the 3/4 holders. Takes about 90 seconds to swap a 1/2in tool.

Nah, it's all MAP Pro or MAP Plus etc. now.
 
Blue works.
Propane torch is fine on larger mills, can get in at gold.
Smaller is harder.
I use a cutting torch with a slight reducing flame usually, even heat.
I really like these, mine are Teknics.
After you do a few, you no longer need to polish the holder to see the oxide progression...
For removal, I clamp the end mill with a vise-grip hanging from a string, spin the whole affair and heat it until it lets go.
 








 
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