WIC 300-315 Envisiontec

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e...w...h

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Any good casting tips?

We used the WIC 402 for a long time with no issues, but we moved to the 315 and started getting all kinds of rings cracking. We changed our cycle to what envisiontec suggested, but no good.
 
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Bigger sprues? Hold at 750F-800F for a while, then go up to high temp.

Use Materialize Magics to "hollow out" the pontics.

I use a .3mm wall thickness setting for PFM bridges on the hollowing function.

.3mm "skin". This does nothing to walls thinner than .6mm, but starts to add an air gap as walls get thicker than .6mm (.3mm skin, then air gap, then the other .3mm skin)

Saves material and aids in burn-out.
 
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You can try non-Envisiontec resin.

Most serious guys end up going that route after you learn where to shop.
 
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e...w...h

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I need to learn where to shop... hint hint ;)
 
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Haven't cast printed patterns yet but this sounds like an old issue when plastic/resin sprues were used years ago. Resin can crack investments as it melts. Must heat soak and use slow rate of climb to prevent cracking !
Use a 2 stage burnout technique which is what Scott is saying. Must run up using a slow heat rate in the first stage and heat soak for 15+ minutes or so. Can't remember the temp while soaking, maybe between 500-700F. Then run up slow, in the 15 F per minute range to your high temp and soak for 1 hr.
This is how I cast large bridges using those 6 and 8 gauge solid plastic sprue bars years ago,,,, (Dipping bars-sprues in wax will help, or using hollow plastic sprues)
A better idea is let Scott print and cast !!!:D
 
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Call Liesegang in Germany and see what wavelegnth your DLP bulb produces, or try to Google it. (Take a peek under the hood and try to find model # of DLP projector or Manuf. It use to be Liesegang in older models.)

Then, go find resin that cures in that range. It's sold in very large quantities for SLA people also. They have a bathtub to fill ya know.
I seriously any of it has much Real Wax in it. Probably 100% plastic because your machine has no heaters.

Add solvent if necessary to maintain viscosity.

Needs to be similar viscosity for similar peeling and dipping etc.

Scott
 
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The safty warning labels that came with your printer should tell you what scary things your printer emits. It should actually tell you the wavelegnth you are trying to shield yourself from with the Orange hood down. Look in the owners manual or PDF of operator instructions.
 
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Im not saying SLA resin wont work...but it might not work very well. SLA typically uses lasers with an output of 325nm to 355nm.

The short arc mercury lamp typical to dlp projectors (the heart of an Etec machine) has a poor output in this range....

aupload.wikimedia.org_wikipedia_en_thumb_9_94_Mercury_Vapour_L18d247eaad8df4360b4df089f73adec1.jpg

Etec primarily uses Irgacure 819 as their photoiniator, Irgacure 369 to a lesser degree, and a very select few use Irgacure 784.

Irgacure 819 (BAPO) CAS#162881-26-7 is also used in many SLA resins however the sensitivity curves allow them to use much less (.01-.1% by weight) then Etec (typical formulated at 1-5%)

If you intend to use an sla resin Id recommend spiking the mix with additional BAPO...sigma aldrich carries it...over priced but if your not buying it by the kg....you wont get much better pricing.

Not to argue with Scott, he really knows his stuff, but despite the lack of heaters there IS wax in the WIC formulas....a polyethylene based synthetic wax added to both weaken the polymer matrix and allow for more rapid burnout due to its lowered melting/vaporization point....did you mean petroleum based wax when you said "real" perhaps? Either way the thinwall and hollow structure recommendations are really the only way to get reasonable success with any photopolymer.

Finally, Id recommend avoiding Etec "dental resins" they are terribly overpriced...
Wic100 or PIC100 at $400/kg are decent alternatives to WIC300 at $989/kg

a good burnout cycle for pic100
Raise temp to 150ºC (300ºF)
5ºC per min
Hold for 3 hours
Raise temp to 370ºC (700ºF)
5ºC per min
Hold for 2 hours
Raise to temp 540ºC (1000ºF)
5ºC per min
Hold for 5 hours
Raise temp to 870ºC (1600ºF)
Normal rate
Hold for 4-5 hours

Oh and the shield....isnt protecting the user nearly as much as it is protecting the resin itself from partial photoinitiation from incidental light.

Hope this helps
aupload.wikimedia.org_wikipedia_en_thumb_9_94_Mercury_Vapour_L18d247eaad8df4360b4df089f73adec1.jpg
 
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That's a really really looong time to be burning out something.

Are you sure that is necessary? I'm sure it works, but that's quite a bit of electricity and waiting and programing on an oven.


(Awesome info! I only know what I think I know from self taught failures. I just have a big mouth, even on the internet)
 
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There are different lamps and DLP projectors for the envisiontec.

I had an old unit with the BIG expensive powerful lamp.

Other units had a much cheaper lamp.

I guess you are in the UV spectrum, so look for stuff that a Xenon lamp would also cure or just ask around. The companys that make resin will know what you are talking about for sure!


No?
 
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TECHARTISAN

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That's a really really looong time to be burning out something.

Are you sure that is necessary? I'm sure it works, but that's quite a bit of electricity and waiting and programing on an oven.


(Awesome info! I only know what I think I know from self taught failures. I just have a big mouth, even on the internet)

Its a platinum burnout cycle....I probably should have abbreviated....My post seemed long so I just pasted from one of my files....

The critical portion is the first two steps...
Raise temp to 150ºC (300ºF)
5ºC per min
Hold for 3 hours

The hold time is necessary when casting medium trees....for smaller castings you can reduce the time....but too short and youll find cracking an issue....so it takes some experimenting.

Raise temp to 370ºC (700ºF)
5ºC per min
Hold for 2 hours

I find that lower hold time here to be undesirable....but again it depends largely on the overall mass of your castings and the investment.

After that its dependent on your particular investment.

In my experience the worst casting issues are caused by speedy temperatures....but Ive read rumors that your a real oven juggler...so maybe you have some tricks Ive not had luck with...I have one large burnout with a computer controller I use for an entire "casting day"....so my methods may be madness for the average end user.
 
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There are different lamps and DLP projectors for the envisiontec.

I had an old unit with the BIG expensive powerful lamp.

Other units had a much cheaper lamp.

I guess you are in the UV spectrum, so look for stuff that a Xenon lamp would also cure or just ask around. The companys that make resin will know what you are talking about for sure!


No?

Etec's machines use UHP (p-vip) lamps..their resins operate in the nearUV...capitalizing on the spike shown above around 405nm.

The bulb inside the $1000-1500 proprietary replacement lamp housing can be extracted and replaced with the same model Osram p-vip for $80-150....if you dont mind getting your hands dirty....oh and probably voiding your Etec warranty :(

Xenon flash lamps are used in their post cure, but like most xenon curing lamps the power density is much higher then what the actual DLP exposure unit produces. Consequentially, most of your traditional UV cure materials just dont work.

The build limitation of the etec's single material build eventually soured me on the whole concept...most of my interest in 3d modelling and prototyping suffers unacceptably when support removal comes into play....
I still try to lend what support I can to the hobbyists trying to replicate Etec on a budget, there has been one sucessful replica, whose creator has been teasing the hobby community with an "open source" gone "closed source seeking a patent and big profits" for nearly a year now.

My own interest has shifted towards multijet modelling, having become quite enamored with the InvisionHR I helped my former boss acquire from you a few years ago, Ive been working on a xerox hack for half a year already and expect to be at it at least another 12 months before I get the results Im hoping for....but thats a matter for a different forum entirely :)
 
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e...w...h

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Thanks for all the info, guys! Very helpful and complete!
 
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My old 3d printer had the BIG UV bulb in it from envisiontec. The blb was around $500 direct from bulb manuf.

I think you are getting two different DLP projectors mixed up.
I had the perfactory mini multi lens. While is may say mini in the name, it was a full size machine with the larger UV bulb and projector was from leisegang in Germany. Parts were further cured in a UV chamber if that helps?
 
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ewh, we use WIC315 with our envisiontec printer. this is our burnout procedure for casting. it's also listed on our website (cap-us.com) if you go to products>wax>burnout procedures.

Microstar HS 1/ 100g package to 16 ml/MS liquid plus 9 H2O
Bench set for 12-13 minutes
Burnout speed @1475 degrees Farenheit 45 minutes and cast (for 100
grams)




Full Gold Crowns (JMC):


Microstar HS 1100g package to 13 ml / MS liquid plus 12 H2O
Bench set for 12-13 minutes
Burnout speed 1475 degrees Farenheit for 45 minutes
Reduce temp to 1175 degrees Farenheit for 30 minutes and cast
 
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You are missing info there buddy....

What is the ramp rate or I guess you are calling it the burnout speed?

Most guys are holding half-way at 750-800F or so for a while (half hour pre ring)...then resuming the ramp up to high temp at a slow-med rate. The plastic ooze4s kinda slow starting at 750F and if you go too fast up to high temp, you will get casting fins from cracked investment or even exploding rings!

It's unclear to me if you even started with a cold oven?
 
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Scott,
CAP YK is saying we put the ring into the preheated oven that is at 1475 F. No ramp rate, no ring splitting or flash. We have the oven preheated to the max temp and soak it for the 30-40 minutes. The bench set time is absolutely critical. You need to get the ring in the oven at the peak point in the thermal reaction. This is when the ring is at the hottest point when sitting on the bench. You will know it is time to put it in the oben when it is almost too hot to handle.
 
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thanks for the clarification, bob

Scott,
CAP YK is saying we put the ring into the preheated oven that is at 1475 F. No ramp rate, no ring splitting or flash. We have the oven preheated to the max temp and soak it for the 30-40 minutes. The bench set time is absolutely critical. You need to get the ring in the oven at the peak point in the thermal reaction. This is when the ring is at the hottest point when sitting on the bench. You will know it is time to put it in the oben when it is almost too hot to handle.
 
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