Tuesday, June 25, 2013

WAGR GC and/or MR AC wagon 3D printed

****NEWS FLASH****


See below

For those that have not seen the 3D printed GC wagon I bought to the last AMRA Meeting, I thought I should post this up, this is my first post on the Blog and its just a quick one to see how it goes.

The photos are a bit blurry at the moment Im not technically skilled as a photographer and I cant find the macro button on my point and shoot.

This was printed in Prime Gray from iMaterialise like Richards R Class, but I have seen there are issues with the latest prints from them, and I wont be offering them for sale just yet until this issues are resolved as I think results may vary otherwise.

I have ordered a couple from Shapeways after a couple of alterations to improve the original, will have to see if they come out as good. And I have confirmed the shape of the chassis from AMRM issue 154 (thanks to Andy May).

More to come as they say.

Update: Painted, undecaled photos

****** Update ******

Those of you whom saw the GC wagon's last Monday would have a good idea of what I have been up to I have made this available for purchase through Shapeways, as of this evening.

I will be putting up both a molded bearing version (slip in wheels) and an untested brass bearing insert compatible version (due to some peoples desire for this option). I will order one of these to check it comes back for a good fit.

Why Shapeways and White Strong and Flexible (WSF aka Polyamide) rather than Prime Gray (PG) (by i.Materialise).

Firstly i.Materialise recently unilaterally changed the minimal detail size they will print in PG according to their Website (due to wishing to use a lower resolution printer (probably due to cost of processing). This is their prerogative but they did so while some customers had ordered believing that items would be printed correctly (the website hadn't been changed at that time), but they did not reprint using the technology they have in the past used and they have not remedied that situation. - Under Australian consumer law they should be liable for refund to customers but it remains to be seen what the remedy they will implement.

Frankly to rant on; as a 3D print bureau this is laughable behavior not only because of the customer service end, but these guys are being surpassed by home based 3D printers at almost a tenth of the cost (see formlabs.com). Good luck to them by the time they figure this out they would have lost a bunch of customers. Technology marches on the best thing about 3D printing is the resolution gets better and cheaper over time.

Secondly is cost vs detail balance.

The WSF material is stronger than Prime Gray (PG) and from three feet away, you can't hardly notice the detail difference between the two. WSF as a material is certainly capable of similar resolution in my opinion to our cast resin kits in many ways. Although due to the fine detail in my drawing of the GC rivet detail is noticeably missing from the print (see below) but if an item was designed for this material I think rivet detail is possible and equivalent to resin (you can see the tie down rings did come out on the print the same size as a rivet on a typical wagon as inspected under a magnifying glass.)

WSF does have the major disadvantage to PG, it requires a bit of work to get to look good. It has a pretty rough surface similar to 320 grit sandpaper, but I have found REPCO "Spray Putty" or similar Automotive primer/filler smooths out the rough texture well, this wagon above needed 1 dust coat of primer and 2 wet coats of the Spray Putty to look like this with out any polishing or rubbing down.
Most detail is still visible despite this process as you can see.

WSF comes in on this wagon at around about equal (maybe slightly higher) in cost to making the resin equivalent by Greg at GA Models, but a lot less work. This price though may not be that scale-able to larger items as the more volume of plastic the model has the higher the cost to produce, though this is partly true with the cost of production on cast resin, the 3D print will increase linearly by volume but the parts for "a single kit" of a wagon may continue to cost similar value with larger wagons compared to smaller etc.

Frosted Detail (FD) at Shapeways

FD is another option for those wanting a GC, this material is quite capable of similar (now even better, due to print technology changes by iM) resolution to PG, but with a slightly rougher surface, it is also difficult to clean the waxy residue that is left on the model due to the printing process, it appears on my printing a common issue occurred and that is the wax support structure got partially integrated with the plastic of the print and created a rougher surface which requires work to clean up unlike PG.

Shapeways recommends a process on their website, but a good scrub with dish soap and then a bath with white spirits does a reasonable job to start with.

NB: The main issue with the FD is that some items were broken off I am sure during post processing and the model will need repair and replacement of broken parts if you get one so be warned (this did not happen with PG by i.Materialise)


So for those interested in 3D printing you can now order a copy in WSF or FD, but I am willing to take orders to make it a bit cheaper (I have six drop-in wheels molded baring WSF on the way) I can offer for sale $25.

You will need to compleate: Kadees (medium underset shank), paint, 12x26mm spoked wheels (Railwest), and 0.5mm brass wire for brake rodding.

I am getting a PG GC from iMaterialise (soon I hope) to see if my model will print in their new process but it seems to be taking a very long time. If that is successful I will put that up as an option as well.

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