Marbelup

I print through I.Materialise and they don’t have a problem printing multiple copies of the same part on a sprue. A couple of years ago, they formalised their sprue requirement to ensure small parts don’t get lost, as that was their main concern previously. Since then, they haven’t objected to any of my sprued designs including, for example, 12 identical parts to make 3 pairs of bogies.

Surprising to get a size error of that magnitude. Where has the error crept in? I would assume the STL files are the correct size?

An old venetian blind slat could work for the roof, especially if you can get one from an older house with the wider slats. I have a stock of them which I have used in the past for 4 wheel vans and a small railmotor.

If designing a multi-part model in PLA or similar, you can “weld” parts together using a fine tipped soldering iron. I mostly use Colorfabb PLA/PHA blend for larger models as it is less prone to warping.

It might need additional supports? Did you take a photo prior to removing supports, or a screenshot of the automatically generated supports? Curious that you have included the coupler mount, presumably for Kadees or similar? Body mounted couplers generally perform better, e.g. with much less risk of derailment when pushing a train.

Don't expect to be able to print items in scale thickness, e.g. if representing metal prototype parts. The minimum printable thickness very much depends on the type of printer being used. For example, I work on 0.5 mm minimum thickness for small details and 0.8-1.5 mm for main body parts, as these suit I.Materialise SLA print capabilities. (Some small resin printers can print considerably finer, I know.) Strictly speaking, I.Materialise specify 1 mm wall thickness as absolute minimum and I have to take risk/responsibility for anything less. For something like a hopper or open wagon, I design the body to true scale dimensions outside then remove the inside to achieve the desired wall thickness. Thus the visible top of the sides is thicker than scale, but the same goes for commercial plastic models. Sometimes, I disguise thicker-than-scale parts, e.g. brake gear levers, by bevelling the rear edges so the visible edges appear thinner while the part is still reasonable robust.

I printed some test bogies in i.Materialise grey resin a few years ago. I found that if I made the sideframes thin enough to flex to insert the wheelsets, then they tended to spread over time with the weight of the wagon on the pinpoint bearings. So, I tried thickening up the sideframes so that they are quite rigid, and printing the bogie in 2 pieces, as per attached screenshot, which are held together with screws. This approach has been successful. I do use standard brass bearings press fitted into holes in the sideframes. I have also printed a 1-piece bogie in which the brass bearings are pressed in from below, to fit the wheelset. This works provided the axlebox/bearing is large enough to have at least 0.5 mm material either side of the slot which houses the brass bearing. I haven't tried including the conical bearing hole in the 3D print, so I don't know how it would wear over time. My bogies are in Sn3.5 scale but wagon size/weight is similar to other 16.5 mm gauge models.

You could try asking for an exemption given that you are bringing your business to IM rather than Shapeways, and that the design of the models is proven by previous printing. Just a thought. Also, is it your intention to print your locomotive in many parts to be assembled as a "kit"? I do the opposite, and try to minimise the number of parts, to 1 if possible. I understand that, especially with a steam loco, it might be desirable to print different parts in different orientation to minimise stepping on curved surfaces. IM do allow parts to be "sprued" now, with certain conditions, which I now use for small parts like bogies to minimise the impact of the €5 fixed charge per part.

I haven't used it myself, but I know other 3D modellers using Autodesk Fusion 360 which is free for hobbyists. Would that be another option?

Large curves should not get "planked" if you use decent CAD software and use appropriate settings when exporting STL file. I have done several cylindrical hopper wagons in HO and S scales and the curved sides come out quite smoothly apart from some stepping towards the top due to the printing process itself. The hopper in the attached photo is S scale and printed by i.Materialise in their standard resin. The sides have not been smoothed at all and 2 coats of paint have been applied.

Looking back at the photos from June 8, 2016, I am pretty sure the layering on the sides of the wagons is the residue from the wax support material used for Shapeways FUD. I haven't ordered from Shapeways since I first started out in 3D in 2012, as I wasn't impressed by the residue, although some people seem to get good results with FUD. I have had some success on wagons with similar overhangs by making the underside of the overhang slope upwards, which can elimate the need for supports of any kind while not being too obvious on the finished model. An example is the C-channel side sill in the screenshot. I usually print in i.Materialise Standard Resin and, prior to that, their Grey Resin.

Narrow Planet sell products from Tyneside Models so, if all else fails, they might pass on a message for you. Their web site is https://shop.narrowplanet.co.uk/ and they have a good old- fashioned email address.

I just sent a message to Tyneside Models via Shapeways to let them know Harold has been trying to contact them. I can understand Harold's issues as the message appears as a Forum "conversation" with 2 "members" but there is no confirmation of the recipient's identity. The messaging system is all a bit vague. I am not a regular Shapeways customer, but I do have a login. I do order fairly frequently from i.Materialise, because I prefer their Standard Resin material.

The message form appears when I tried it.

Sven, what software did you use to generate the supports form this model?