3D printers - messin' with resin

[AndyB]

Hi Martin,

Based on a bit more digging I think you are correct. I'll probably give it a shot without supports for no other reason that it will simplify things if I can get away with it

The printer is "warming up" now and I'm thinking of giving it a go tonight. Stay tuned!

BTW, the rubber gasket for the lid won't stay put on mine. It's a bit too big. I might just apply a bit of RTV but I should probably ask for a new one.

My Ultra Violent light won't be here till Monday but it's supposed to be sunny here tomorrow which might be sufficient to cure something assuming it does not go in the bin first.

Cheers,
Andy

 

[Martin Wynne]

BTW, the rubber gasket for the lid won't stay put on mine. It's a bit too big. I might just apply a bit of RTV but I should probably ask for a new one.

Mine seemed to be the same. But after getting it on and firmly pressed down all round it has stayed on, and seems to have tightened up after a few hours. Or at least it hasn't come off after much handling of the lid.

I'm a bit puzzled why your lid needs a rubber seal if you don't have the air purifier option? The lid for the washer doesn't have the seal, but is otherwise identical and interchangeable. With IPA sloshing about inside, I would have thought it could do with a seal too.

cheers,

Martin.

 

[Martin Wynne]

The Elegoo build plate is 140mm x 80mm.

The longest standard timber is 19ft-6in, to reach across a double track crossover at 6ft way.

That's 78mm in 4mm/ft scale, so will just fit width-wise if you get the model precisely centred on the plate.

And 136.5mm in 7mm/ft scale, so will just fit length-wise if you get the model precisely centred on the plate.

Elegoo seem to be telling us something by giving the build plate an aspect ratio of 7:4 .

edit: forget that, the exposure screen is only 129mm long.

Martin.

 

[AndyB]

Yikes! It worked. I think the small amount of "flash" is a consequence of not elevating the first layer above the build plate. Uncured as yet. Will it survive insertion of the rail after curing? Stay tuned for further exciting episodes of "Track: Have it your way."

 

[Tom Allen]

regarding the "flashing", count how many initial layers are over exposed and draw this section smaller on the model.

 

[Tom Allen]

All set up and ready to go:

View attachment 524

Just waiting for the IPA, which should be here this evening.

This corner is where all the original work on Templot was done, as you can guess from the Delphi2 chart on the wall. I've left it up for old time's sake.

But for the last 10 years it has been a dumping ground for several derelict computers, monitors, old printers, and the rest. Plus a lot of other assorted junk. It's taken me several hours to restore it to this usable state. This room isn't used much, so I can set the printer going and shut the door on it to keep the fumes contained. Also I've discovered that the fan on the Elegoo Plus model is quite noisy and could get annoying, so being able to shut the door on it is a help. I'm not yet sure I've made the right choice in going for the one with an air filter.

It won't look like this for long.

cheers,

Martin.

A good addition to your setup would be a shallow baking tray, and sit the printer in the tray making sure the tray is at least twice the size of the printer base. It's really easy to drip resin, and an absolute pain to deal with.

 

[Tom Allen]

Also spills of resin which will happen, trust me, however small need to be dealt with so plenty of heavy duty kitchen towel will be needed. I'm quite lucky and i seem to be pretty safe when it comes to "resin on the skin", but i have seen some really nasty reactions to resin. So nitrile gloves seem to be the safest way to go, but be brave and try a bit on your skin, you may be ok. I went through a whole box of gloves before i realised it does'nt bother me.

 

[Jim Guthrie]

Martin,

It's worth trying building directly on the plate even with smaller items like chairs. I've printed spoke centres for wagon wheels in S scale directly on the plate and they worked well. I reckon that the surface area of a split spoke centre of a wheel in contact with the build plate would be close to that of the base of a 4mm scale or S scale chair. This would also mean that the base of a chair was flat - printing a chair up on supports could mean having to treat the base of each chair printed to make sure they are flat - depends how the chairs are orientated. It might be worth a bit of experimenting, taking care to clean out your resin tank if something has dropped off.

I find that a roughened surface to the build plate helps to keep parts stuck to the plate. My first printer - a Phrozen Shuffle 2018 - was supplied with a build plate already roughened. My present printer - a Phrozen Sonic Mini 4X - was supplied with a smooth build plate but the accessories supplied included a small sheet of coarse sand paper if you wanted to roughen the plate's surface, which I did. What's really important is that the build plate is flat. There are occasional reports of plates being warped on new printers out of the box so if you have continual problems with parts not sticking, it's worth checking this.

The metal scraper to get parts off the plate needs to be really sharp these days to get things off the plate. The rafts on my 2018 printer were relatively thick which allowed a fairly sharp scraper to get under the lip created. But my current slicer produces much thinner rafts and therefore a much smaller gap under the lip and the metal scraper I have won't get into the gap. So I use a Stanley knife blade to get under the corner of a raft and lift it a little, then the metal scraper can get under that edge and remove the whole part. A sharp wood chisel would also do the job. The metal scraper can mark the plate sometimes but no worse than the sandpaper.

As you get experience, you will probably find that the key art to master in 3D printing is orientation of the part(s) and placement of supports.

Jim.

 

[Tom Allen]

Agreed on the build plate being roughened a bit. The print is always trying to stick to the FEP, it's just the natural order of things, so we have to coax the print to favour the build plate. My printer is an original Photon, and after a while i sanded the build plate which made a considerable difference, but it did have a downside, the print was a lot harder to remove.
Important rules, level the machine well, then level the build plate even better, the more time you spend getting the build plate correct the better the resuts. I've adopted the four corner approach, rather than one sheet of paper, far better.

 

[Matt M.]

Hi Tom,

Just because you don't have a reaction to resins now doesn't mean you won't develop one.
Sensitisation is an issue.

I know someone who built 1/43rd model cars for living. Never had a problem till he did.
Coughing up blood and such other joys. Ended up working in a book store.
Can't do modelling with any form of plastics and glues.

Keep your gloves on and the liquid resin off your skin. Avoid breathing the fumes.
When working with the finished product control the dust and don't inhale that either.

Regards, Matt M.

 

[Tom Allen]

Thanks Matt, it is always better to be safe.
As an old engineer my hands have taken a fair bit of rough treatment over the years, and once when a new type of coolant was tried out and ending up attacking everyones hands, i seemed to be quite immune to it.

 

[Charles Orr]

Hi Martin,
Some of the YouTube reviews for this printer say not to bother with the plastic tool but use the metal scraper to remove parts from the build plate.

Inspired by your enthusiasm I have a set of similar items arriving from Amazon shortly including a Mercury Plus Wash and Cure unit and the 2 Pro printer.

Charles

 

[Matt M.]

No problems Allen. I worked in the sign and display industry for a number of years,
before and after leaving school, and have seen some poor outcomes for long
term workers. The automotive industry, which I spent 10 years as a spare parts
interpreter, has had some fails as well.

Build up of toxicity seems to be an issue so I have always played safe.
Keeping all of it out of your lungs is a big one.

Matt M.

 

[Martin Wynne]

Keep your gloves on and the liquid resin off your skin. Avoid breathing the fumes.
When working with the finished product control the dust and don't inhale that either.

Hi Matt,

Thanks for the warning. I find wearing gloves very uncomfortable and make my hands sweat.

Is this stuff any good against the resin? I've always used it for engineering jobs, degreasing, etc., and never had any problems:

https://www.toolstation.com/rozalex-dri-guard-barrier-cream/p80597

Martin.

 

[Martin Wynne]

A good addition to your setup would be a shallow baking tray, and sit the printer in the tray making sure the tray is at least twice the size of the printer base. It's really easy to drip resin, and an absolute pain to deal with.

Thanks Tom.

Now installed in the biggest baking tray I could find. I couldn't get the tray to sit flat on the shelf, so I have used a bit of sponge rubber mat under each corner of the tray. Which has had the beneficial effect of damping the noise from the printer fan.

It meant re-levelling the printer by fiddling with the adjustable feet all over again, but I got there in the end. It's always a pleasure to use my grandfather's engineer's spirit level.

I may perhaps return the Bibo to where it was before, and gain more working space for the printer. Time will tell what's the most convenient arrangement.

cheers,

Martin.

 

[Martin Wynne]

Yikes! It worked

Hi Andy.

Well done, looks great.

How thick are those sleepers and webs?

Martin.

 

[Martin Wynne]

I find that a roughened surface to the build plate helps to keep parts stuck to the plate.

Hi Jim,

Thanks for the tips.

The Elegoo build plate is supplied ready sand-blasted. It's dead flat end-to-end, but fractionally convex side-to-side. Only by a couple of thou, so not likely to be a problem.

For my intended design, it doesn't matter if the base of a chair is not dead flat, the base clearance leaves space for some glue, although I'm hoping I can make them clip-fit:

On the other hand, the base plug needs to be a precise dimension without any flash, so will probably have to be done on supports.

I have a cheapo window scraper, which is just a Stanley-type blade in a plastic handle, but works fine on the Bibo.

The supplied Elegoo metal scraper is a good quality with a ground edge and polished blade. I'm surprised at the quality of the tools supplied with the Chinese machine. The Allen keys are ball-ended, and the genuine Xuron snips will come in very handy.

cheers,

Martin.

 

[Martin Wynne]

Inspired by your enthusiasm I have a set of similar items arriving from Amazon shortly including a Mercury Plus Wash and Cure unit and the 2 Pro printer.

Hi Charles,

Great! Between all of us we should be able to fathom this thing out.

cheers,

Martin.

 

[AndyB]

Hi Andy.

Well done, looks great.

How thick are those sleepers and webs?

Martin.

Hi Martin,

The sleepers are drawn 1.10 mm thick but measure 1.0 mm. Webs drawn 0.60 measure 0.56.

When I cured it in sunlight the sleepers bowed slightly. Up at the ends. IIRC the resin does shrink a bit when cured.

The chairs support the rail quite well and I have not managed to break any yet. The gauge is 0.1 mm narrow, but that might be my drawing. (It was originally a test panel for my filament printer.)

Don't do what I did. I left the resin in the vat/tank and covered it with cling-film. It developed a skin like custard overnight. I managed to get it off but punctured the FEP in the process. Fortunately I already ordered some FEP and it should be here tomorrow.

Cheers,
Andy

 

[Tom Allen]

resin can be left in the vat for days with no harm coming to it, as long as your cover is uv proof. If you're not sure cover the printer with the box it came in or a heavy duty garden quality bin bag, i've done both.
There are many subtle things to watch out for with resin printers, joining a model specific facebook group or forum will be a good start.

 

[Martin Wynne]

resin can be left in the vat for days with no harm coming to it, as long as your cover is uv proof. If you're not sure cover the printer with the box it came in or a heavy duty garden quality bin bag, i've done both.

Hi Tom,

My thought was to use aluminium cooking foil?

Do you leave the tank in place on the printer, or remove it to a flat surface so that it can be parcelled up entirely in foil?

cheers,

Martin.

 

[Martin Wynne]

I managed to get it off but punctured the FEP in the process. Fortunately I already ordered some FEP and it should be here tomorrow.

Hi Andy,

Bad luck.

There should have been 2 spare FEPs in the box. The bag has a label on it not to throw them away!

Just reading good info here about changing the Elegoo FEP:

https://www.scalefour.org/forum/viewtopic.php?p=83053#p83053

cheers,

Martin.

 

[Martin Wynne]

Google is your FEP friend:

Fluorinated Ethylene Propylene was invented by DuPont and is sold under the brand name Teflon.

Martin.

 

[AndyB]

Hi Martin,

No spare FEP with mine but the stuff I ordered from Amazon came in the mail today.

One thing I noticed is that the slicer is a bit different form the slicer I use with my filament printer. It does not care if there are blocks embedded in other parts but the Elegoo version does not seem to automatically integrate everything into a single solid or surface. I had to do a logical add of all the parts in my model to make them into a single surface.

I'll do some investigating.

Andy

 

[Martin Wynne]

Hi Andy,

I'm struggling with the slicer too. I've got a stack of chairs ready to print, and assumed it would add a support under each one. But it's getting in a complete muddle -- 2 supports on some chairs and none on others:

I'm going to have to add the supports in Templot.

p.s. notice the random screw heads and key offsets. I'm wondering if it will be visible in 4mm scale?

Further work needed on the plugs, draft angles, etc., but first I want to see what will and won't print.

cheers,

Martin.

 

[Matt M.]

HI Martin,

Barrier Cream is useful stuff. I use it working on cars but with gloves as well.
That is a workplace standard these days. That physical barrier is important.

I also end up with sweaty hands but you do get used to it. You shouldn't
be wearing them for too long, just while you are handling the unset chemicals
and if you are wet sanding the finished product.

Try to find a brand that fits as closely as possible. It helps with the comfort
if they fit your palm and length of fingers properly. Those little bits of extra
finger length make picking up small items very hard.

The longest continuous use I have these days is at New South Wales State Archives and
Records were I will be wearing them for four hours straight at times while handling
NSWGR plans. Typing in them is a bit crap though.

Matt M.

 

[AndyB]

That resin is indeed nasty stuff. Despite limited exposure yesterday the aroma has been haunting me all day. I think I'll have to make myself a fume cabinet.

 

[Jim Guthrie]

I'm struggling with the slicer too. I've got a stack of chairs ready to print, and assumed it would add a support under each one. But it's getting in a complete muddle -- 2 supports on some chairs and none on others:

I'm going to have to add the supports in Templot.

Martin,

Don't do that. You'll curse the day you did when you maybe want to change the orientation or modify supports for any reason and you have to go back to Templot to do it. Your slicer should allow you to add, delete and edit your supports. I find that the auto generation of supports by the slicer I use - Chitubox - can be a bit peculiar with model railway subjects. I think the algorithms might be geared up to do the figures for war-gaming. I find that it's almost automatic for me to edit an auto generation and with a recent wagon body, I found it better to do all the supports myself which was quicker than modifying an auto-generation.

Jim.

 

[Matt M.]

Hi Andy,

A respirator is a useful and from my point of view mandatory bit of kit.
3M and Norton supply good ones but it is better to see if you can try
one on for fit and comfort.

They do have to seal well so you should test it against a perfume or
something less toxic. Put on and adjust, twist your head around and
check that the seal stays sealed. You shouldn't smell anything.

Full face is best, especially when sanding plastics and wood for dust
protection but half face is possibly easier if you have the multiple
glasses for focal length issue.

After that you are moving into fume filters (my choice for soldering),
which are more expensive and the justification would be the amount
of time you spend in that environment.

Matt M.

 

[Martin Wynne]

One thing I noticed is that the slicer is a bit different form the slicer I use with my filament printer. It does not care if there are blocks embedded in other parts but the Elegoo version does not seem to automatically integrate everything into a single solid or surface. I had to do a logical add of all the parts in my model to make them into a single surface.

I'll do some investigating.

Hi Andy,

I've had a torrid morning trying to get the Chitubox slicer to accept STL files which were fine on the Bibo. Tried to make sense of several mesh repair tools. Got nowhere. One program I tried told me I was making a big mistake using STL files which were nearly always broken, and I should use OBJ files instead.

Then I found this online STL repair service:

https://www.formware.co/onlinestlrepair

Brilliant. Upload STL. Wait 3 minutes while nothing seems to be happening. Download repaired STL.

Bingo, Chitubox loads it and slices it without errors.

Of course I'm not really using STL files. I'm creating DXF files in Templot, but DXF seems to be unknown in the 3D printing world. I'm using TurboCAD simply as a converter to convert DXF to STL. It doesn't support OBJ files.

edit: Templot can now export STL files directly.

---

edit: First results from printer here:

https://85a.uk/templot/club/index.php?threads/229/

cheers,

Martin.

 

[Tom Allen]

i bought a Hazmat suit when i first started, but it made my hands sweat.

 

[Tom Allen]

boiled egg?

 

[Martin Wynne]

boiled egg?

No, roast beef and yorkshire pudding (had a boiled egg before I started printing, just to be sure).

Martin.

 

[AndyB]

They look great Martin!

(I fixed the resin tank. Not difficult at all but thank goodness for power screwdrivers. Lots of little screws.)

 

[Charles Orr]

They look excellent Martin.

 

[Matt M.]

Hi Tony,

The original paper full body suits used in spray painting were bad enough.

Took care of an elderly relative in hospital ten years ago who was in
isolation due to possible VRE infection. Wrapped in plastic PPE but head
free. 4 hours at a time twice a day.
In a humid Australian summer with no air-conditioning.
That equaled 2 loads of washing at 10 o'clock in the evening.
Talk about damp...

 

[AndyB]

Very pleased with the first results.

The CAD:

View attachment 568
Straight off the printer -- 4mm scale (difficult to photograph without any paint):

View attachment 567

View attachment 566

View attachment 565

View attachment 564

View attachment 563

I will write some more after a meal.

cheers,

Martin.

Hi Martin,

Have you considered making the "plugs" cylindrical rather than rectangular, or even with two cylinders (Lego?) to maintain alignment?

It would not be difficult to make hardened drilling jigs for ply sleepers in 00, 00-SF, EM, P4 etc., etc.

Cheers,
Andy

 

[Tom Allen]

Thinking about gauge widening and angled chairs on points, would this be dealt with on the sleepers?

 

[Jim Guthrie]

Very pleased with the first results.


Straight off the printer -- 4mm scale (difficult to photograph without any paint):

Those look good. Congratulations.

Jim.

 

[Hayfield]

Stunning !!!