3D Printing in 2mm Scale

[Crosland]

I have narrowed my choice down to a mono resin printer:

 

Elegoo Mars 2 pro: available now from Amazon at £275

Phrozen Sonic Mini 4K: Similar build volume, better resolution 35um v 52 um, £360 but no stock

Phrozen Sonic Mighty 4K: Much larger build volume but do I really need it for 2mm?. Being 4K does not improve resolution due to larger build plate area. £550 but no stock

 

I ruled out Anycubic Photon Mono as being more expensive for similar specs.

 

I am tempted to get the Elegoo from Amazon before the Xmas rush as there is no guarantee Phrozen will honour quoted lead times.

 

Any thoughts?

[bill-lobb]

54 minutes ago, Crosland said:

 

How does the multiple printing work? Do you need to "step and repeat" in the design software or does the slicer do it for you?

 

 I can't speak for all, but the Chitubox slicer allows you to copy the same thing multiple times.

 

Bill

[Sithlord75]

1 hour ago, Crosland said:

 

How does the multiple printing work? Do you need to "step and repeat" in the design software or does the slicer do it for you?

 

I set up on wagon body on the bed (angle, supports etc) then copy it, position the copies and then slice.  Multiple prints merely require selecting the slice file again.

[richbrummitt]

2 hours ago, Crosland said:

I have narrowed my choice down to a mono resin printer:

 

Elegoo Mars 2 pro: available now from Amazon at £275

Phrozen Sonic Mini 4K: Similar build volume, better resolution 35um v 52 um, £360 but no stock

Phrozen Sonic Mighty 4K: Much larger build volume but do I really need it for 2mm?. Being 4K does not improve resolution due to larger build plate area. £550 but no stock

 

I ruled out Anycubic Photon Mono as being more expensive for similar specs.

 

I am tempted to get the Elegoo from Amazon before the Xmas rush as there is no guarantee Phrozen will honour quoted lead times.

 

Any thoughts?

I recently went through the same mental argument and bought the Mars 2 Pro. It was in stock and I think it is large enough to print everything I’m likely to want to do. I also read that the Elegoo support is good and that it was easy to use. If I find that my calculation about size of item is not correct in the future I can upgrade to a larger machine later at a significant cost increase. I’m only just starting to use it in anger so cannot comment further (especially with no experience of the others in your list) except that I found it is easy to set up and use. That is until you get to the cleaning up: I am now looking into wash and cure stations. It’s a slippery slope now I fear. 

[Crosland]

5 minutes ago, richbrummitt said:

I recently went through the same mental argument and bought the Mars 2 Pro. It was in stock and I think it is large enough to print everything I’m likely to want to do. I also read that the Elegoo support is good and that it was easy to use. If I find that my calculation about size of item is not correct in the future I can upgrade to a larger machine later at a significant cost increase. I’m only just starting to use it in anger so cannot comment further (especially with no experience of the others in your list) except that I found it is easy to set up and use. That is until you get to the cleaning up: I am now looking into wash and cure stations. It’s a slippery slope now I fear. 

 

Thanks, that gives me confidence about my choice.

 

Having posted I decided I couldn't wait and ordered the Mars 2 Pro, a curing machine, and a selection of resins.

 

[Kris]

46 minutes ago, Crosland said:

 

Thanks, that gives me confidence about my choice.

 

Having posted I decided I couldn't wait and ordered the Mars 2 Pro, a curing machine, and a selection of resins.

 

Good choice that. Make sure you register with Elegoo. Doing that used to get you a couple of free screens. 

[richbrummitt]

52 minutes ago, Crosland said:

 

Thanks, that gives me confidence about my choice.

 

Having posted I decided I couldn't wait and ordered the Mars 2 Pro, a curing machine, and a selection of resins.

 

Probably wise if you were going to click to buy; stock of some of the printers seems to yo-yo constantly and this seems the be one of them. 
 

I bought a mercury cure station having read good things about it but wish I’d have saved that money and got a wash and cure straight away.

 

The resin has a shelf life. The elegoo resin I got from that rainforest/jungle retailer at the same time as the printer is good until July next year according to the bottle. I would say stocking up on resin is only worthwhile if you know you’re going to use it within the shelf life. 

[Crosland]

20 minutes ago, richbrummitt said:

I would say stocking up on resin is only worthwhile if you know you’re going to use it within the shelf life. 

 

I'm not thinking straight. I originally added some water washable and some ABS-like to my basket but then decided not to bother, for exactly this reason, so hopefully I have not bought too much.

[Crosland]

I was pleasantly surprised what was included in the "tool kit" with the Mars 2 Pro

 

 

Not 100% certain what they are all for yet

 

Sithlord of this parish has kindly sent me an .stl via the 2mm association .stl exchange so I have no excuse...

 

As a complete novice, opening the file in the slicer, orienting it ( a few degrees thisaway, a few degrees thataway...), adding supports, creating multiple copies with varying orientations was all very easy, very little learning curve. The slicing took hardly any time. For some reason I thought I had read it could take a loooong time.

 

[nick_bastable]

On 14/11/2020 at 14:27, Crosland said:

 

I'm not thinking straight. I originally added some water washable and some ABS-like to my basket but then decided not to bother, for exactly this reason, so hopefully I have not bought too much.

due to environmental issues and disposal  I use water washable resin  although it may not be as friendly as I think

 

Nick B

[Atso]

Another PO wagon being designed. I was looking at the prices of new RTR wagons and decided I needed a different route to the remaining c. 50 I need. Kit's, while cheaper, still ended up totaling an eye watering amount so I decided to have a go at the CAD. I've still got a way to go, but I think it is shaping up nicely so far.

[alangdance]

Ordered the Mars 2 Pro today from Amazon and got it for £186. Now back at £230.

 

Alan

[alangdance]

Sorry it was a Mars Pro not a Mar 2 Pro.Still a good price.

Edited November 15, 2020 by alangdance

[drduncan]

Dear all,

 

I'm dipping my toe in 2mm  3D (as a dyed in the wool 4mm chap my excuse is I want to do something special for my son's - gasp - N gauge....)  So here is a GWR 46'6" E19/E20 (one was BG - and yes I've done that too just not in 2mm  - the other narrow/standard gauge and I'm not sure which) standard gauge brake tricomposite of 1888/9.  Hopefully I'll see later this week if scaling down from the 4mm version works or whether lots of thickening up of sides and panels is needed.  Fingers crossed!

 

My boy also wants a Great Bear for his N -gauge too!

 

Regards,

 

Duncan

[richbrummitt]

The washing really makes a difference. These are from exactly the same slice file on the same day but the light got to the first one before I had cleaned well enough. 
 

 

 

10 points* for anyone who correctly identifies the type of axle box from the not so good phone snap of the print. 
 

I’ve decided it’s worth persevering with printing things though and ordered a washing station to go alongside the printer. 
 

*points are not exchangeable for anything, have no cash (or other) value whatsoever and bragging rights cannot be assured. 

Edited November 17, 2020 by richbrummitt
more to say

[Nick Mitchell]

1 hour ago, richbrummitt said:

10 points* for anyone who correctly identifies the type of axle box from the not so good phone snap of the print. 

 

GWR OK type?

[Chris Higgs]

4 hours ago, Nick Mitchell said:

 

GWR OK type?

 

yes, but which journal size?

[richbrummitt]

14 hours ago, Nick Mitchell said:

 

GWR OK type?

 

Close enough. It's based on the OK F drawing. It is missing the top up oil filler however.

 

9 hours ago, Chris Higgs said:

 

yes, but which journal size?

 

1mm x 0.8mm was the intention in an attempt to fit over the top hat bearings without modification. As you are aware this is not possible at scale size so I scaled it 110% to get the hole in. That could make the size 8.8 x 4.4 in. The hole has gone AWOL on the printed item though even though the bolts on the sides have come out! 

 

[garethashenden]

5 hours ago, richbrummitt said:

 The hole has gone AWOL on the printed item though even though the bolts on the sides have come out! 

 

 

Try printing the axlebox vertically. I bet the hole is there, but resin got trapped in it.

[njee20]

Good choice on the Mars 2 Pro, I'm enjoying mine!

 

Resin lasts a good while, and you'll go through it fairly quickly. I've got at least 15 litres 'in stock'! Worth buying some when it's cheap!

I agree that the water washable isn't all that eco-friendly. You can't dispose of the contaminated water down the drain or anything, the only real difference is the ability to use water versus IPA for cleaning, but the additional cost of the resin is more than the cost of IPA - personally I'd stick with standard resins, they seem to be a bit more stable once cured too.

[richbrummitt]

22 minutes ago, garethashenden said:

I bet the hole is there, but resin got trapped in it.

 

Absolutely. Then I cured it further to be sure! I can try lifting the item prior to slicing too but not something I've done yet. These can be drilled out to fit, which means modelling still occurs...

[Jan W]

I have a question about wall thickness for coaches.

From what I have read it seems that a wall thickness of approx. 1mm is recommended.

This would give problems with glazing, like the old rtr offerings.

If I draw a coach with a recess on the inside around the window aperture and leave a wall thickness of 0.4mm, would that print well?

I did something similar with a Dapol autocoach where I milled a recess for the glazing material on the inside.

 

I seems that buying my own printer will also be cheaper than printing through Shapeways.

The coaches I want to build are available on Shapeways but would cost around €75,- (incl. shipping costs). If I add that to the few parts that I already had them printed I would have spent half the cost of my own printer.

And I would make more use of 3D printing because it would be affordable...

 

Jan

 

[richbrummitt]

43 minutes ago, Jan W said:

I have a question about wall thickness for coaches.

From what I have read it seems that a wall thickness of approx. 1mm is recommended.

This would give problems with glazing, like the old rtr offerings.

If I draw a coach with a recess on the inside around the window aperture and leave a wall thickness of 0.4mm, would that print well?

I did something similar with a Dapol autocoach where I milled a recess for the glazing material on the inside.

 

I printed a Beetle C model the other day on my Mars Pro 2 that I previously had done at Shapeways circa 2010. I don’t need another but it is a good model for a test because it has lots of different types of features on it. There are panels on the door, droplights, louvred, planks, thin sections, strapping and rivets. 
 

The shapeways model is better because it hasn’t warped, the rivets are visible and there are no holes where there should not be holes. Once the learning curve has built up to my aspirations I hope to not have those issues. 
 

The minimum wall thickness in this model is 0.4mm. The nominal wall thickness is 0.7mm and there are peripheral details that are less than 0.3mm. It is where the wall thickness is 0.4mm or below where I have seen some tearing from the DLP process. There is some optimisation to be done but I believe what you are looking for is possible with this kind of printer. Certainly @Sithlord75 has printed PO wagons with comparably thin side walls. 
 

As an aside the smallest detail on the axle boxes I showed just up the thread is below 0.1mm I believe. I drew it full size and scaled it without bothering to measure anything afterwards but put a 1mm hole in the back for a bearing. The shank of the 5/8”? bolt is visible. I wouldn’t expect to see that on a model from shapeways. 
 

Hope that helps. 

[Yorkshire Square]

23 hours ago, richbrummitt said:

 

The hole has gone AWOL on the printed item though even though the bolts on the sides have come out! 

 

 

If you print a part directly onto the build plate you will get "bleed" in the first few layers due to the extra exposure time. Either print the part on raised supports or build a sacrificial skirting into your model. Or both, if necessary.

[Kylestrome]

There is one aspect of 3d modelling/CAD for 3d printing that I've never been able to understand, probably because it's obvious to everyone else but me. When you have a model ready to export as an STL, does it have to be combined as a single object with a continuous surface or can it remain as a group of separate objects?

 

David