Selection of the material for the jig of special purpose

[hubihubi2]

Hi All,

I would like to ask you for some advice regarding to material selection for designed jig.
The size of the jig will be approx. 20mm(H)x180mm(L)x120mm(W).
The jig will have some groovings etched on its top surface. The heating coil (max 1000W, 230/240V) will be inserted into those groovings every ~1minute and powered for approx. 10sec.
I need to select the material for that jig which would fulfil the following requirements:
- nonconductive (electricity),
- low-abrasiveness,
- capable of withstanding temperatures up to ~1050C,
- machinable material (to mill the grooves on one of its surfaces and bring to it some curvature shape).

I think that good choice could be some type of the ceramic or composite material.

I would be very appreciated for your opinion and help.

Thank you.

Greetings,

Hubert

 

[cloa]

Way too hot for plastic composites.

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[RPstress]

1050°C (1920°F) too hot for almost everything! Non-conductive so no metals or a bunch of stainless/superalloys would work. A few ceramics might be applicable. Machinable ceramic is rare but more common than you might think.

o Macor might work, but low abrasion is questionable, though it can be polished. See

http://accuratus.com/macorfab.html

.
o Maybe Shapal:

http://www.dynacer.com/data-sheets/machineable-ceramics/

, though it may be even more brittle than Macor.
o Maybe Rescor L56 if it can be protected from air at temperature? See

http://www.cotronics.com/vo/cotr/cm_machinable.htm

for machinable glass and alumina and

http://www.cotronics.com/vo/cotr/pdf/915.56L.pdf

for the graphite.
o Machinable boron nitride?

http://www.bn.saint-gobain.com/combat-bn-solids.aspx

.
o Some of the Cotronics materials are claimed to be easily castable. That might make grooves, etc., independent of machinability.

http://www.cotronics.com/vo/cotr/cm_castable.htm

.

Caution: I have no practical experience of these materials. The only ceramics I've dealt with were for simple washers taking high compression.

 

[cloa]

What are the strength and rigidity requirements and how long is it at 1050C- sounds like only short term and is there possibility of atmospheric control like no oxygen?
How about a nett process like powder metallurgy to overcome machinability needs? Not too hot for metal/ceramic composite if the metal is tungsten or one of the other refractory metals.

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[hubihubi2]

Hi All,

Thank you for your replies.

@cloa
Yes, the plastic composites would not be suitable for the material for this jig.
Strength requirements- the jig will not be loaded with any significant force.
Rigidity- Yes, the jig should remain rigid during its operation. There is some small thermal deflection allowed (+/_0.5mm).
Time of heating the coil in the jig - the coil will be inserted into jig's groovings every ~1minute and powered for approx. 10sec.
Atmospheric control- this solution cannot be considered for this project.
Powder metallurgy- yes, I will explore this solution .

@RPstress
Macor- I have just requested sample package from the dealer of this material for tests. Indeed, it might be a good solution if element is polished.
I am also familiarizing with the rest of the materials that you have given in your reply.


I am very appreciated for all your advices. Thank you.

Regards,

Hubert