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There has been a lot of discussion about WSF and FUD  for 3D printing. Please no more here.

 

Looking at Shapeways list of materials, and they have added PLA to the botton, initially for makers only.

Now I know PLA is biodegadable, so will degrade, but given the current climate with respect to plastic waste, I think it and other biodegrable plastics will be used more in the future. I am more worried by talk of plastic gobling chemicals/enzymes being created, as they could find themselves somewhere they should not be.

 

I know that for engineering type models, then PLA is not that good, but for static models,or larger scale ones, the cost benefits might outweigh the disadvantages. Make something out of card, and if it gets wet it s ruined, even wood, yet many are happy to use these materials.

Someone told me PLA would absord liquid, so maybe coating it in something which gets absorbed wlll help preserve it. Ihave found that this happens wih WSF.

 

I was surprised how some of my designs actually pased the auto checks for PLA. For larger scales(O and G1), even WSF is not cheap, but PLA is cheaper.

 

So apart from maybe testing a design,home printing?, has anyone tried it for proper models.

 

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As far as I know, the commercial printers offering PLA use an extrusion type printer, so the result is not that much different to home printers. Having used a home printer (Makerbot) for a few years now, there are a few serious issue. Where supports are needed, the supports, if done in PLA, are too strong and very difficult to remove without damaging delicate parts of the model. Dual head printers can do supports in other materials, such as PVA which is water soluble, but I found there was poor adhesion between the different materials. I also found that larger models in PLA (say, > 150 mm) are prone to warping and pulling away from the build platform. I have had better result, in terms of warping, with PLA/PHA blend filament, but it can still be a problem. I have printed some functional parts, including a rotary car dumper, in PLA/PHA and have not had any problems with degradation over several years. I mainly use the Makerbot for prototypes to test the fit of parts, where the lack of detail (compared to SLA prints) is not an issue. Where possible, I try to arrange prints so supports are not needed, even if that means joining several parts to complete the model, which can be done quite easily by "welding" with a soldering iron. In some cases, I have designed my own support structure 'which can be easier to remove than the automatically generated supports. I have printed some larger test models, such as large diesels in S scale (around 300 mm long) in 3 sections which are "welded" together. These prints were useful to test the fit of the bogies and drive mechanism, but the finish and detail were not suitable as a finished model.

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As far as I know, the commercial printers offering PLA use an extrusion type printer, so the result is not that much different to home printers. Having used a home printer (Makerbot) for a few years now, there are a few serious issue. Where supports are needed, the supports, if done in PLA, are too strong and very difficult to remove without damaging delicate parts of the model. Dual head printers can do supports in other materials, such as PVA which is water soluble, but I found there was poor adhesion between the different materials. I also found that larger models in PLA (say, > 150 mm) are prone to warping and pulling away from the build platform. I have had better result, in terms of warping, with PLA/PHA blend filament, but it can still be a problem. I have printed some functional parts, including a rotary car dumper, in PLA/PHA and have not had any problems with degradation over several years. I mainly use the Makerbot for prototypes to test the fit of parts, where the lack of detail (compared to SLA prints) is not an issue. Where possible, I try to arrange prints so supports are not needed, even if that means joining several parts to complete the model, which can be done quite easily by "welding" with a soldering iron. In some cases, I have designed my own support structure 'which can be easier to remove than the automatically generated supports. I have printed some larger test models, such as large diesels in S scale (around 300 mm long) in 3 sections which are "welded" together. These prints were useful to test the fit of the bogies and drive mechanism, but the finish and detail were not suitable as a finished model.

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The issue about some detail not being as good is less of a concern to me. It is for big chunky items such as Gauge 1 wagon bodies, and some OO scale buildings that I am tempted to try it for. For a building that would cost over £100 in WSF, it comes down to about £40, which might make it viable. For G1 wagon bodies a small coal wagon body drops fom £30 to £18. A van body would probably have a bigger saving. Not sure if I would us it forchassis, but complete wagon with chassis is about £25 copared to £55 for WSF but no floor in wagon, so ad a bit for that, but probably no more tan £30, which is not too bad for a gauge 1 wagon, just paint, and wheels etc to add.

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I have used Shapeways for PLA previously and found the quality to be poorer than cheap home printers.

 

The picture below shows a 4mm PHA wagon hopper with a shapeways print on the left and one from my own printer on the right.  The fact Shapeways even though it was good enough to send out makes me wonder what a poor quality print from them would look like.  That Shapeways print made me decide to buy my own printer - Shapeways did do a reprint of the hopper but it wasn't as good as my own print.

 

28427049509_cc0ef26323_k.jpg4mm PHA hopper prints by simon br blue, on Flickr

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interesting. I suspect Shapeways are still testing, possibly outsourcing the production. I would not want it for OO scale, as the price difference with WSF is not enough.

 

Like with other plastic options, one fit does not fit all, and depending on size/scale of models you want done, will determine best option. The problem for 4mm scale railway items is that they fall in the middle, not small enough to be cheap enough in best quality, and too big cost wise(partly because r2r prices are artificially low. Forcing prices down is not lways best policy long term, as it is not sustainable.

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As luck would have it I've printed a 16t mineral wagon body in 1/32 scale.  The picture below is the first print, I've now done a second print with a couple of modifications including printing the end door detail separately as top surface (when the wagon was turned up the correct way) wasn't smooth.

 

27731056008_a269ce5321_k.jpg1.32 16t mineral body by simon br blue, on Flickr

 

I've also had a couple of prints done of a 1/32 scale Presflo hopper, like the mineral body this was printed upside-down and the top surface is rough and needs covering up. 

 

37002526716_2028b192b9_k.jpg1/32 presflo hopper by simon br blue, on Flickr

 

37020782892_ff5c4cefb4_k.jpg1/32 Presflo Hopper by simon br blue, on Flickr

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