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Posted by Winston on April 30, 2008, 1:08 am
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rpseguin wrote:
(...)
> I was just thinking that one of those would make a cheap source for
> the control electronics and the coils look flexible enough to reshape/
> reuse from the one response showing somebody taking one apart.
It'd be much faster and cheaper to weld short vertical tube sections
to the cooking surface of a steel frying pan. You could match the ID
of the tubes to the OD of your collets plus some headroom.
Pack Kaowool in the gaps and Bob's your uncle.
Corrosion control is left as an exercise for the student.
They also make a great gag gift.
--Winston
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Posted by rpseguin on May 1, 2008, 6:46 pm
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> It'd be much faster and cheaper to weld short vertical tube sections
> to the cooking surface of a steel frying pan. You could match the ID
> of the tubes to the OD of your collets plus some headroom.
> Pack Kaowool in the gaps and Bob's your uncle.
While that may be faster to fabricate, it sounds like it would be a
lot less efficient in heating the endmill holder quickly.
Will the induction properly feed all the way up the tubes and then
induction heat the endmill holder through an air gap insulation?
Ie, while the tubes may get hot quickly, will the endmill holder get
hot fast via induction? Or just slowly via radiation/convection/
conduction?
Looking at this image:
http://en.wikipedia.org/wiki/Image:Induction_Cooker.jpg
I think it is worth a $100 experiment to see about reshaping the coils
to be up close to the endmill holder.
Take it back to the store: This thing came this way, with all the
wires hanging out and it smelled like smoke when I opened the
package :-)
(just kidding, I would never do that)
Thanks.
-Ralph
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Posted by Ed Huntress on May 1, 2008, 8:47 pm
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>> It'd be much faster and cheaper to weld short vertical tube sections
>> to the cooking surface of a steel frying pan. You could match the ID
>> of the tubes to the OD of your collets plus some headroom.
>> Pack Kaowool in the gaps and Bob's your uncle.
>
> While that may be faster to fabricate, it sounds like it would be a
> lot less efficient in heating the endmill holder quickly.
> Will the induction properly feed all the way up the tubes and then
> induction heat the endmill holder through an air gap insulation?
> Ie, while the tubes may get hot quickly, will the endmill holder get
> hot fast via induction? Or just slowly via radiation/convection/
> conduction?
>
> Looking at this image:
> http://en.wikipedia.org/wiki/Image:Induction_Cooker.jpg
>
> I think it is worth a $100 experiment to see about reshaping the coils
> to be up close to the endmill holder.
> Take it back to the store: This thing came this way, with all the
> wires hanging out and it smelled like smoke when I opened the
> package :-)
> (just kidding, I would never do that)
>
> Thanks.
> -Ralph
I haven't followed this thread so excuse me if this has been covered, but I
hope you know that the hard part with induction-heated heat-shrink
toolholders is not getting the tool in and clamping it, but getting the tool
*out*. If you even slightly overheat the holder before you put the tool in,
or if your induction heater is just a wee bit slow, you'll never get the
tool out. Sophisticated systems, like Bilz's ThermoGrip, involve a *lot* of
timing experiments in the course of their development.
All of which is OK if you're planning on making a permanent toolholder/tool
assembly. d8-)
--
Ed Huntress
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Posted by rpseguin on May 1, 2008, 9:55 pm
Please log in for more thread options > I haven't followed this thread so excuse me if this has been covered, but I
> hope you know that the hard part with induction-heated heat-shrink
> toolholders is not getting the tool in and clamping it, but getting the tool
> *out*. If you even slightly overheat the holder before you put the tool in,
> or if your induction heater is just a wee bit slow, you'll never get the
> tool out. Sophisticated systems, like Bilz's ThermoGrip, involve a *lot* of
> timing experiments in the course of their development.
I believe it. That was one of the things I was wondering about. How
do you avoid induction heating of the endmill/tooling?
Or, does the "gap"/interface between the tool and the holder decouple
it enough to allow differential heating.
> All of which is OK if you're planning on making a permanent toolholder/tool
> assembly. d8-)
Well, I guess I'll try a drill chuck first :-) If all else fails,
I've got a permanently mounted drill chuck on a BT40 shank :-)
Thanks.
-Ralph
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Posted by Ed Huntress on May 1, 2008, 11:10 pm
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>> I haven't followed this thread so excuse me if this has been covered, but
>> I
>> hope you know that the hard part with induction-heated heat-shrink
>> toolholders is not getting the tool in and clamping it, but getting the
>> tool
>> *out*. If you even slightly overheat the holder before you put the tool
>> in,
>> or if your induction heater is just a wee bit slow, you'll never get the
>> tool out. Sophisticated systems, like Bilz's ThermoGrip, involve a *lot*
>> of
>> timing experiments in the course of their development.
>
> I believe it. That was one of the things I was wondering about. How
> do you avoid induction heating of the endmill/tooling?
> Or, does the "gap"/interface between the tool and the holder decouple
> it enough to allow differential heating.
They avoid heating the tool by heating the holder so fast that heat doesn't
have a chance to conduct in to the tool shank. If it does, you're a dead
duck when you try to get the tool out.
The clamping results in a very tight interference fit, so conduction between
the holder and the tool is practically uninterrupted. You don't gain any
significant edge from the transition between toolholder and tool insulating
the two from each other. The bore of the tooholder is actually cool enough
to touch, as is the tool shank, at the instant the holder releases its grip.
Power is critical and the timing for applying the removal force is critical.
They work in seconds.
>
>> All of which is OK if you're planning on making a permanent
>> toolholder/tool
>> assembly. d8-)
>
> Well, I guess I'll try a drill chuck first :-) If all else fails,
> I've got a permanently mounted drill chuck on a BT40 shank :-)
>
> Thanks.
> -Ralph
Ha! Well, that would solve the problem.
I wrote quite a bit about these gadgets when they were first becoming
popular, and they are really great for the appropriate applications. But
"appropriate applications" are high-speed milling with some horsepower.
Unless you're spinning the tool at something over 10,000 or 15,000 rpm,
with, say, 10 or 20 horsepower, their advantages are not very great. Of
course, once you've invested in one of the things, it's worth using it for
your ordinary tooling and speeds, too, if you're running multiple machining
centers and you have a big inventory of tools. I've never heard of anyone
using shrink tooling with a drill chuck, but I guess it would be OK if you
also had your MC tooled with multicoated or ceramic inserts, running at the
max.
Otherwise, the conventional solutions are a lot less trouble and expense.
--
Ed Huntress
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> the control electronics and the coils look flexible enough to reshape/
> reuse from the one response showing somebody taking one apart.