Anycubic Photon

[PiperguyUMD]

Printed some hoppers this afternoon that had .0010 holes for grab irons. There were usable pilot holes present but the rest of the print failed 

[peteski]

Most aquarium heaters have a safety to shut off when there is no water.

I was thinking that the heater would be immersed in the liquid resin. Maybe not? 

[AlwaysSolutions]

I was reading somewhere a guy used a couple low wattage light bulbs inside the chamber on the back side.  Kind of like an easy-bake oven setup if you remember that kids toy a looong time ago.  That might be something simple that could be rigged up.  Of course whether that works would probably depend on how cold it is.  I'm only dealing with ~50 deg F so that might be worth trying out.

[Mark W]

Since I print in the garage I've been heating my vat/resin prior to printing and it helps a lot with the viscosity issues.

I wonder how much this would actually be helping?  By the time your print gets past supports and to the actual part, temperature of the vat will almost certainly have reached thermal equilibrium with the rest of the garage. 

A heat lamp might work to provide a constant, even source of heat, but I'd want to make sure they don't put off any UV themselves.  Usually they are more on the IR side of things though.

Another option is a "Lens Warmer".  Manufacturered warmers are wrapped around a lens body and meant to keep the camera lens above freezing during long outdoor cold weather shoots to prevent fog and condensation.  They probably wont provide enough power to heat a resin vat to the 70-80 F range, but surely the smart minds here could design a high-output type warmer!   I believe they're essentially just a string of resistors.  That raises the question of diminishing returns though, the power required to get such a circuit to output a consistent 70-80 degrees, wrapped around the vat for hours on end, might be more than it's worth.   
 

[narrowminded]

For clarity on the viscosity difference I've seen, it's all been at the same temperature, 69/ 70 degrees F.  The observed difference is the resin alone. 

My only concern with using heat beyond room temperature is the fear that it'll have a bearing on the cure rate.  That fear originates in using 2 part epoxies which are definitely effected but are also based on heat to cure.  But then, there is reference to this in a white paper from Formlabs about curing resin and they find that the strength is increased, so it has an effect on resin, too.  And the temperature they are finding that matters is right around 150F which happens to be the same range that 2 part epoxies are effected, to the good.  I suspect there is a relationship here but that's just a deduction with no specific knowledge as to why.

Edit add:  This heating wasn't referencing heating the vat when generating the part but heating the post cure, the light box.  After Mark W posted his response I realized that this response wasn't clear on that.  Sorry if it created confusion.

[Mark W]

...white paper from Formlabs about curing resin and they find that the strength is increased...

Do you have a link? 

I read a similar paper (that I can no longer find) which I understood the conclusion was that temperature had little to no affect on the prints end strength.  Just that higher temperature greatly reduced the necessary layer cure time, resulting in faster prints.  It didn't consider effects on details though. 

[narrowminded]

Do you have a link? 

I read a similar paper (that I can no longer find) which I understood the conclusion was that temperature had little to no affect on the prints end strength.  Just that higher temperature greatly reduced the necessary layer cure time, resulting in faster prints.  It didn't consider effects on details though. 

I wonder how much this would actually be helping?  By the time your print gets past supports and to the actual part, temperature of the vat will almost certainly have reached thermal equilibrium with the rest of the garage. 

A heat lamp might work to provide a constant, even source of heat, but I'd want to make sure they don't put off any UV themselves.  Usually they are more on the IR side of things though.

Another option is a "Lens Warmer".  Manufacturered warmers are wrapped around a lens body and meant to keep the camera lens above freezing during long outdoor cold weather shoots to prevent fog and condensation.  They probably wont provide enough power to heat a resin vat to the 70-80 F range, but surely the smart minds here could design a high-output type warmer!   I believe they're essentially just a string of resistors.  That raises the question of diminishing returns though, the power required to get such a circuit to output a consistent 70-80 degrees, wrapped around the vat for hours on end, might be more than it's worth. 

I would need to know something specific about this working or not and if helpful, what temperature.  The mechanics of adding something would be too involved to just take experimental stabs at it and I also suspect that the information that would suggest this is or isn't helpful would be known to the resin manufacturers and further, would already be in use on at least the higher end machines.  Is it?

In the meantime, for really low temperature garage environments, a small enclosure that houses just the unit and was equipped with just one or two incandescent lamps to bring the temp up to a typical household would probably be sufficient.  And a thermostat could be added easy enough.

[narrowminded]

Do you have a link? 

I read a similar paper (that I can no longer find) which I understood the conclusion was that temperature had little to no affect on the prints end strength.  Just that higher temperature greatly reduced the necessary layer cure time, resulting in faster prints.  It didn't consider effects on details though.

Not handy but I could look.  It was Formlabs who did it and you had to give your info to read it.  And this wasn't about heating the resin but heating the completed parts during post cure.  A heated oven with the UV light.

[narrowminded]

Do you have a link? 

I read a similar paper (that I can no longer find) which I understood the conclusion was that temperature had little to no affect on the prints end strength.  Just that higher temperature greatly reduced the necessary layer cure time, resulting in faster prints.  It didn't consider effects on details though.

Just musing about this, what's the real benefit vs: the cost?  At least for most of us.  On an unattended machine, unless the cycle time is critical to production volume, a change of even double the time just isn't that critical.  And if it is, at the level we're operating, would a second machine maybe be just as cheap or cheaper than the time, effort, and material to rig a heater to one machine?  If the numbers work, go for it.  But I suspect that any fair analysis will suggest you schedule better and when that's no longer enough, add a machine.  

Then, spend the rest of that time that would have been spent squeezing pennies out of the present, developing new products to sell to your customers who are already satisfied with your products and already bought all you are offering that they can use.  Spend your time developing the next thing they want.  That's the business side of me speaking.

[peteski]

Another option is a "Lens Warmer".  Manufacturered warmers are wrapped around a lens body and meant to keep the camera lens above freezing during long outdoor cold weather shoots to prevent fog and condensation.  They probably wont provide enough power to heat a resin vat to the 70-80 F range, but surely the smart minds here could design a high-output type warmer!   I believe they're essentially just a string of resistors.  That raises the question of diminishing returns though, the power required to get such a circuit to output a consistent 70-80 degrees, wrapped around the vat for hours on end, might be more than it's worth. 

All electric heaters are resistors.    Well, almost all. A Peltier module is a semiconductor heat pump.  But I digress.

I don't think a high power consumption will be an issue.  I use a food dehydrator to speed up paint drying of my models and to speed up cure of urethane resins and RTV rubber.  It is a cylinder about 14" i diameter and about 12" high.  It has some adjustable slots to circulate the air and a 40W heating element on the bottom.  That 40W heater keeps the temperature inside the dehydrator at about 120 F.  It is just like having a 40W bulb turned on in your house.

The 3D printer would probably need a bit more powerful heater (because it is not enclosed like the dehydrator, but I don't think it would need to be more than a 100W.

[BuffaloJohn]

I'm not so sure that adding a heater to the resin vat is a practical idea, nor do I think it would be effective. Heating the room where the printer is located is probably the only reasonable idea. There are plenty of things inside the printer that don't want to be overheated (LEDs are on a heatsink already and the electronics/motors/lube/etc work best when the temp is stable and in the Goldilocks zone).

The problem with any heater is going to be heat distribution. The higher the thermal gradient, the further away from the heater the machine and resin needs to be. The vat won't heat very well as it is an AL frame. The build plate needs to be the same temp as the resin, otherwise it just cools down or heats up the resin - adding yet another variable. Any heater is going to need a controller of some sort (thermostat is the simplest type). The printer "room" could be an insulated box in which the printer can be housed and the climate for the printer maintained. One needs to know the heat generated by running the machine and how much heat is lost through the insulation and then you can figure out how much heat you need to add to the "room" to keep the printer at it's optimum temp (probably 25c would be a good target). It is also possible that the printer in an insulated "room" might generate more heat than you can dissipate through the insulation, so now you actually need to figure out how to cool it.

John

[narrowminded]

Do you have a link? 

I read a similar paper (that I can no longer find) which I understood the conclusion was that temperature had little to no affect on the prints end strength.  Just that higher temperature greatly reduced the necessary layer cure time, resulting in faster prints.  It didn't consider effects on details though.

@Mark W  Found it.  Enjoy!   https://formlabs.com/mechanical-properties-of-uv-cured-3d-prints/

Try this one.  I think you can get it without signing up for anything.  https://docplayer.net/24051948-Formlabs-white-paper-how-mechanical-properties-of-stereolithography-3d-prints-are-affected-by-uv-curing-by-zachary-zguris-phd-formlabs.html

[AlwaysSolutions]

I searched "triangles" on the Facebooks and found a post were they said you can use a Photon validator and take the slice with the triangles out and fix in MS Paint, the replace it.

Sorry to dust this one off - I've been battling this issue now for a couple of days on one of my models.  The same effect, but was so subtle that I didn't really notice until one print where it went haywire and I checked the preview, line by line and saw the same thing you were getting: one layer planes that don't exist in the model.  What I found is that the slicer just kind of sucks - simple as that.  It's not anything wrong with your model.  The slicer is having a hard time dealing with intersections of separate objects that have planar surfaces in close proximity and occasionally just makes stuff up.  In the end, I found that if I feed it a solid object, as opposed to several objects for it to deal with - it behaves.  I don't recall what software you're using to make your models, but if there's a boolean feature that allows you to take multiple objects and permanently join them together into a single object, that may solve this issue for you as opposed to having to find an editor (I looked at this route but was not satisfied there was a decent option for this)  If anyone else experiences this and has success doing what I've outlined I'd like to hear it so we can say with 100% certainty this is a solid workaround.  "Solid workaround" <- PUN intended.   

So, TLDR: If the Photon slicer is making up single layer planes that don't exist in your model, try to boolean your model into a single object, then feed it to the slicer.

Cheers -Mike

[Chris333]

I figured it was the slicer since I would get different results with the same model.


So for my HOn30 empire I just got a brass Climax loco. The pilots are pretty weak looks wise and the is a huge L tongue hanging out to screw a coupler to. So I just 3D printed all new pilots that will hod a 1015 coupler.

Has anyone here used the castable resin and made 3D brass parts?  If so how do you do it?

[robert3985]

I figured it was the slicer since I would get different results with the same model.


So for my HOn30 empire I just got a brass Climax loco. The pilots are pretty weak looks wise and the is a huge L tongue hanging out to screw a coupler to. So I just 3D printed all new pilots that will hod a 1015 coupler.

Has anyone here used the castable resin and made 3D brass parts?  If so how do you do it?

Whatcha do is print the parts using the castable resin, then take your parts to somebody locally who does lost-wax investment casting, and have them cast them in brass for you.  They will tree up the parts, invest them, cast them and throw the hot cannister in a bucket of cold water to crack the hot investment away from the brass castings.  You may need to tell them to do the throwing it in the water thing, as many shops are set up to cast jewelry and throwing castings made of gold or silver can cause the surfaces to do weird things.  Not a problem with brass.

Although I have all of the equipment to do my own castings, it's a lot more convenient for me to have my local rock shop do it for me.  I provide them with the masters that are either wax or Styrene, and I also supply them with the brass to do the castings with, so all they have to do is tree 'em, cast 'em and throw 'em in the bucket.  I'll do the final clean up using an ultrasonic divesting solution in my big ultrasonic cleaner.  The brass comes out bright, clean and ready for final clean-up before soldering and painting.

My rock shop is only charging me $25 a cannister since I'm providing the metal.  Last time I did it, they cast up 125 N-scale switch stands for me in one cannister, so the price per piece is very good.

Note that there is some shrinkage when a wax (castable resin) master is used.  You should talk to your caster to see what they recommend, then compensate for it by modifying your 3D model.

Anyways, that's what I do...and casting up "castable resin" masters will be identical to casting wax masters in a lost-wax investment casting process.

Cheerio!
Bob Gilmore