3D Printing in 2mm Scale

[justin1985]

1 hour ago, Crosland said:

And then the problems started. I want to print what is basically a flat plate about 2.5x10cm and 2mm thick. It has a few holes and some embossed text. I am trying to print it vertically (long edge parallel to the build plate) in order to maximise the number that can be printed at once. The first attempt (with mostly chitubox automatic supports) resulted in only the supports being printed. The remainder was just a blob stuck to the FEP.

 

If it really is a flat plate, and you don't mind a slight "elephant foot" effect on the sides (which could be sanded off) then simply print it completely flat and flush to the built plate! A razor blade type scraper should be able to get it free once printed. 

 

If you do need a detailed rear face etc then raising it with supports will be necessary, but the trick will be to avoid dramatic changes in layer surface area, or if that can't be avoided, design supports to compensate for that. The "leading edge" always needs as many supports as you can possibly squeeze in, for example. If more "weight" is passing through some supports than others, that's when you'll get a support failure.

 

Also, if you're getting not even the supports left on the build plate, then it's worth checking the plate is properly levelled. It's easy to knock out the alignment of the plate from its bracket when scraping off a print (at least it is on the photon - imagine very similar)

 

J

[monkeysarefun]

24 minutes ago, justin1985 said:

If it really is a flat plate, and you don't mind a slight "elephant foot" effect on the sides (which could be sanded off) then simply print it completely flat and flush to the built plate! A razor blade type scraper should be able to get it free once printed. 

I'd do this too. You fit  less copies on the plate but the print time will be a fraction so you can make up for it by the time it takes to do each print.  Also, if you do get an issue you find it after say an hours worth of printing, rather than 5 hours...

 

Otherwise, what are the settings for the base layers? I had issues at the start and so upped mine to something crazy like 180 seconds  per layer.... Solved my problems but I need a jackhammer to get things off my plate.

Edited March 28, 2021 by monkeysarefun

[richbrummitt]

28 minutes ago, monkeysarefun said:

I'd do this too. You fit  less copies on the plate but the print time will be a fraction so you can make up for it by the time it takes to do each print.  Also, if you do get an issue you find it after say an hours worth of printing, rather than 5 hours...

 

Otherwise, what are the settings for the base layers? I had issues at the start and so upped mine to something crazy like 180 seconds  per layer.... Solved my problems but I need a jackhammer to get things off my plate.

Following your advice previously I also changed the settings for the base layers. The exposure time was okay, I think, but I dropped the speed (don’t recall which one of many) to about half. I have a file to process so I can look out what I have and post back here. I’ve a Mars Pro 2 also @Crosland so it might give you a starting point, especially if you’re using elegoo resin. 

[Jan W]

I have never printed anything (I only ordered from Shapeways until now) but from what I read here it seems that you should angle the workpiece relative to the build plate to prevent suction. The edge of your plate is now parallel to the resin and will stick to it. I think?

 

Jan

[MikeTrice]

Jan, suction is not quite as you state. Imagine a hollow tube printed vertically. If the tube is printed flat on the plate it effectively forms a cup when pressed against the FEP forming an enclosed hollow space. When the piece is pulled away from the FEP a suction effect will occur with the trapped space which increases the effort needed to separate from the FEP. This effect can impact the print causing distortions and even splits. If you raise the tube away from the plate and use supports the unvented void does not occur.

 

Unvented voids aside there is a peel force exerted during printing separating the last printed layer from the FEP. Angling the work piece might be to reduce the cross section of the print that needs peeling off or to reduce layer visibility. So in the example in the previous post a thin rectangle can be printed vertically on the plate without a suction effect. Hope that makes sense.

Edited March 29, 2021 by MikeTrice
Typo

[richbrummitt]

This article does a great job of explaining what @Jan W and @MikeTrice are talking about with illustrations. There are actually some interesting articles on the Chitubox website that I found much more useful than a lot of the forum posts from the 3D printing communities that came up in my search results. 

 

@Crosland I found this post from November that detailed the change I made:

 

lift speed reduced from 90 to 60mm/min

[Crosland]

Thanks for all the comments!

 

I was worried printing flat would make it more difficult to remove from the build plate. I tried and that was not the case. The result was OK. Slightly oversize and the letters were not so well defined. These are actually debossed, rather than embossed, as I originally said. (I learned a new word  )

 

I also tried printing one inclined at 20 degrees with the long edge on the plate (rather than the usual few mm lift) and auto supports under the rest of it. This was a better size and the lettering was much more clearly debossed but the two corners on the plate curled up slightly. I'm guessing increasing the bottom layer exposure and/or dropping the speed might help fix that.

 

Is there generally a difference in finished size due to orientation? My flat printed item was slightly larger than the inclined one. Both were slightly too large, so I need to adjust the size of the model slightly.

 

[richbrummitt]

The exposure will alter the size too. You have to overexpose the initial layers to get it to attach to the build plate. If the rest (above the initial layers) is larger than drawn then it is overexposed and the cure time ought to be reduced. 
 

There are lots of calibration pieces available to home settings. Take your pick or do trial and error on something you actually want. 

[SandHutton]

On 28/03/2021 at 17:16, -missy- said:

I haven't clocked it yet but initial checks looks like it is possible,..

I look forward to seeing what the runout is like on the wheels.  from what I could see, they seem to run very true

 

Guy

[justin1985]

On 29/03/2021 at 09:42, richbrummitt said:

There are actually some interesting articles on the Chitubox website that I found much more useful than a lot of the forum posts from the 3D printing communities that came up in my search results. 

 

These are definitely incredibly useful articles! Much better than the confused and repeated advice on Facebook etc forums that seem to be the main communities of resin printer users.

 

But some of the phrasing is ... spectacular ...

 

Quote

Uneven quantity of 3D printing material and tumultuous peeling force among layers result in variable shrinkage which is the main cause of misrun and irregularity.

 

Couldn't have put it better myself!

 

Tumultuous is a word that I feel is not used anywhere enough in describing finescale modelling!

 

(from https://www.chitubox.com/en/article/support/howto/chitubox-free/editing/25 )

[Geordie Exile]

2 hours ago, justin1985 said:

Tumultuous is a word that I feel is not used anywhere enough in finescale modelling 

Whereas "variable shrinkage" can describe many of my attempts!

[Sithlord75]

I feel we need a "nudge nudge wink wink" option...

[nebnoswal]

A little bit of an update.  Recently a member of this parish  show us on the Zoom group his horse box train, and hinted that he would like to add some S&DJR horseboxes.  Challenge accepted.

This is the second draft/print of the short wheelbase, S&DJR 8'6" horse box.  I had 2 reference photos, of No1 and No10, and there are differences between both.  So once I've ironed out the problems with No1, I'll then move onto No10.  It also the first time I've dived in the deep-end and added the torpedo vents as apart of the print

 

Next I will then try the longer variant, with a 11"  wheelbase.

 

Other works in progress are the LMS Prized Cattle Van.  This is getting closer to  completion, just needing to add the torpedo vents

 

Edited April 9, 2021 by nebnoswal
update

[nick_bastable]

16 minutes ago, nebnoswal said:

A little bit of an update.  A member of this parish,  show us on the Zoom group his horse box train, and hinted that he would like to add some S&DJR horseboxes.  Challenge accepted.

This is the second draft of the short wheelbase, S&DJR 8'6" horse box.  I had 2 reference photos, of No1 and No10, and there are differences between both.  So once I've ironed out the problems with No1, I'll then move onto No10.

are these been offered via the 2mm stl exchange ?

 

Nick B

[Sithlord75]

35 minutes ago, nick_bastable said:

are these been offered via the 2mm stl exchange ?

 

Nick B

He'd have to join first wouldn't he? 

[nick_bastable]

21 minutes ago, Sithlord75 said:

He'd have to join first wouldn't he? 

[queensquare]

4 hours ago, nebnoswal said:

A little bit of an update.  Recently a member of this parish  show us on the Zoom group his horse box train, and hinted that he would like to add some S&DJR horseboxes.  Challenge accepted.

This is the second draft/print of the short wheelbase, S&DJR 8'6" horse box.  I had 2 reference photos, of No1 and No10, and there are differences between both.  So once I've ironed out the problems with No1, I'll then move onto No10.  It also the first time I've dived in the deep-end and added the torpedo vents as apart of the print

 

Next I will then try the longer variant, with a 11"  wheelbase.

 

Other works in progress are the LMS Prized Cattle Van.  This is getting closer to  completion, just needing to add the torpedo vents

 

 

That horsebox looks great Ben, nice colour too!

 

jerry

[Sithlord75]

I spent last evening (until 2 this morning as it happens - but when you're on a roll, you're on a roll and The Boss is away for the weekend) drawing up this.  I had first planned on doing it last September and built the chassis to go under a pair of fitted ones but for one reason or another never finished it.  Having now worked out how to use any drawings better (I import them into Adobe Illustrator and then can see what the finished size will be once scaled down but still able to enlarge - I know some 3D CAD programs will let you draw over the top of an import and mine may be one of them but I haven't found the function yet if it is there) I started again and got to this stage in just over 5 hours.  I finished it this morning (the door lock which I had to do both sides as it wasn't able to be mirrored), and after I do the monthly maintenance on the printer, I hope to have a print this afternoon and maybe a finished wagon by the ZAG meeting this evening (AEST Time).  Following Ian Morgan's amendments to his Southern wagons (see @richbrummitt's posts else where) with the cunning supports I've adopted these on this body to see how it goes.

 

[Sithlord75]

 

Poor shot but I got some paint on it and buffers tonight whilst chatting with some ex-students (nice they remember the old bloke who tried to teach them A level History).  Just lettering to go.

[Sithlord75]

Bit over exposed but happy the rivets in the door hinge straps came out.

[MikeTrice]

If anyone is after it eSun Hard Tough resin is back in stock at Amazon uk.

[drduncan]

1 hour ago, MikeTrice said:

If anyone is after it eSun Hard Tough resin is back in stock at Amazon uk.

How does it compare to the ‘usual’ choices like any cubic ?  Is there comparative info on different resins and their best uses? I’m particularly interested in resin that will allow/produce thin walls eg 0.5mm or less (can get 0.7 on a Form 2 with a favourable wind but it’s not my printer) using a proton mono (awaiting mine) to simulate sheet metal on 2 and 4mm locos and rolling stock.

 

Duncan

[MikeTrice]

It is different from more "normal" resins in that you need to give it a post printing heat treatment. As its name suggests it is tougher than normal resins and can be machined. It has gained popularity for use in 3D Printed Wheels.

[Yorkshire Square]

6 hours ago, MikeTrice said:

If anyone is after it eSun Hard Tough resin is back in stock at Amazon uk.

B*gger! Ordered some from Aliexpress only two weeks ago. Possibly stuck in the Suez! 

Edited April 12, 2021 by Yorkshire Square

[Sithlord75]

8 hours ago, drduncan said:

How does it compare to the ‘usual’ choices like any cubic ?  Is there comparative info on different resins and their best uses? I’m particularly interested in resin that will allow/produce thin walls eg 0.5mm or less (can get 0.7 on a Form 2 with a favourable wind but it’s not my printer) using a proton mono (awaiting mine) to simulate sheet metal on 2 and 4mm locos and rolling stock.

 

Duncan

I get 0.4mm walls (with the strapping as an extra 0.1mm) on my RCH prints - but that's with Anycubic black resin in Anycubic Photon printer.  I wasn't successful using Monocure Grey in the same printer.  Haven't tried any other resins.