2mm/N (Simple) Coach Seats

[D869]

I'm contemplating getting some coach seats 3D printed, partly because I need some coach seats and partly because I want to try out 3D printing with something that will hopefully be quick to draw and avoid anything challenging like thin sections.

 

Basically the idea is to keep things very simple - no armrests etc and produce some generic coach seat shapes that can be used inside compartment or open stock. The seats might be painted or might be covered with paper printed with something resembling seating fabric.

 

The same generic seat shape is extruded (using OpenSCAD) into several widths - 11.5mm, 7mm, 5.5mm and 3.5mm to allow options for compartment stock plus 2+2 and 2+1 open seconds and firsts. Each width has 16 copies (32 for the 5.5mm) to allow an 8 bay coach to be done. All in all it should be possible to do 3 coaches with one print.

 

The key dimensions of the seat shape are - 7.5mm high, 4mm front to back, squab max 2.5mm from floor.

 

Shapeways want $11.49 to print in 'White Strong and Flexible' or $29.91 in FUD.

 

I thought I'd ask for some feedback before handing over any money.

 

Some (lots of) questions...

 

- Have I got the shape and size roughly correct?

- Cost-wise, is this a sensible number of seats to have in a single order or would it be better to have more or less?

- Is it worth making a recess in the bottom to reduce material usage?

- I'm thinking that I don't need FUD for this, but what would be suitable?

- I have sprued each set of 16 together with a 0.5mm square sprue at floor level. Is this big enough?

- I haven't added any sprues in the other direction, so each set of 16 is physically separate from the others. Should I sprue the strips together?

 

Thanks in advance for any advice.

[Wild Boar Fell]

Hello D689,

Good to see new interest in 3D printing,

Looking at your render (2D Image), you could probably get away with doing it in WSF so long as the chair back goes no thinner than 0.7mm. If it is thinner then FUD will allow it to go down to 0.3mm. You would however have to thicken up your sprue to the same 0.7mm or if any dimension (probably the sprue) is longer than 117mm if needs to be thicker see http://www.shapeways.com/materials/strong-flexible-design-guidelines, Also you would have to sprue between the rows of seats as well to allow it to be seen as one file. Depending on the size of the base of the seats, you may be able to hollow them out slightly which could bring your costs down further but the wall thickness rules would still have to be met + the difference may be minuscule anyway.

Hope this helps,

Regards,

Wild Boar Fell

[D869]

Looking at your render (2D Image), you could probably get away with doing it in WSF so long as the chair back goes no thinner than 0.7mm. If it is thinner then FUD will allow it to go down to 0.3mm.

Thanks for the advice.

 

It's 0.6mm at the bottom of the padding for the passenger's head but I could probably live with making it 0.1mm thicker (and having fatter sprues) if it brings the cost down so much.

 

Regards, Andy

[Marbelup]

Have you considered other online printers, e.g. i.Materialise.  They have a range of materials too.

 

Although it won't make a lot of difference, it is usually worth hollowing out solid areas to save print volume providing the hollow is accessible for clean-up of support materials as per supplier's guidelines.

[edubs]

i materialise wont do anything connected by sprues.

[D869]

Thanks for the advice so far.

 

An update... I've revised the 3D model to include 0.7mm square sprues in both directions and also hollow out the underside of the seat, leaving 0.7mm of material all around the hollow.

 

I also made the seat back 0.7mm at its thinnest point and lowered it to 7mm because 7.5mm seemed to be towards the upper end of the height range for a coach seat.

 

The updated model is now priced at $9.50 in WSF, so I'd say that the hollows have been worthwhile.

 

I had a look at iMaterialise but wasn't sure which materials to look at. I've seen 'Prime Gray' suggested elsewhere but this is 1mm min thickness, which is a bit much for what I want. I'll probably go with Shapeways for this one because I need to go with somebody.

 

I was also pondering (purely theoretically) whether to scale the model up and allow HO and 4mm people to use it but as far as I can see a straight scale up to 4mm would have 8 times the volume and would cost 8 times the price. Even if I managed to perfectly thin everything back down to 0.7mm I reckon I could not possibly do any better than 4 times the price, both of which seem like a lot of money for some simple coach seats whereas $9.50 for three coaches in 2mm scale doesn't seem too terrible. Am I missing something here?

 

Regards, Andy

[Etched Pixels]

Ok my thoughts would be

 

- FUD you want a block of them because the pricing is $5 + volume while in WSF is basically by volume.

- Subtract what you can out of the inside in each case - that can save you a fair few pennies and makes it lighter. At the least you can make the base of the chair hollow. You may even be able to lose the front base of the seat - it'll glue to the sides and you can't see under seats anyway !

 

Pricing then will depend whether the thinner walls allowed with FUD outweigh the cheaper but thicker WSF. In this case my guess is not.

[D869]

I've just put my order in with Shapeways so now I'll wait and see what happens.

 

Regards, Andy

[D869]

Just arrived from Shapeways...

 

 

These seem to have come out very well. They are a little fuzzy compared to some FUD bits that I ordered at the same time but still a big improvement on making them from card. I can certainly live with a little fuzziness for a coach interior given the difference in price.

 

The only slight surprise was that the crossways sprues don't seem to have printed well so all of the seating rows came adrift from each other. I re-checked the model and the sprues are the same size (0.7mm square) in both directions so I guess that this is something to do with printing orientation. Not a problem given that the sprues will be cut off anyway.

 

Thanks to everyone who sent comments.

 

Regards, Andy

[Nile]

Looking good Andy.

A 0.7mm sq. sprue is going to be a bit weak and may break with handling.I'd go for 1mm sq. minimum.These prints get blasted with an air line to remove the unused powder.

[-missy-]

Excellent work there Andy.

 

I was just looking into doing something similar but I dont think I will bother now! The only difference I was thinking about was to produce a single length of seat profile and then cut it to length.

 

Can I be cheeky and ask how much it cost to get those printed?

 

Missy

[D869]

Excellent work there Andy.

 

I was just looking into doing something similar but I dont think I will bother now! The only difference I was thinking about was to produce a single length of seat profile and then cut it to length.

 

Can I be cheeky and ask how much it cost to get those printed?

Thanks Julia.

 

They are showing up at 8.90 Euros now, which is what they cost me, plus shipping. I think that shipping was shared across the whole order - I bought some of your SC Buffers at the same time.

 

I'm not sure how the 'shop' thing works on Shapeways and whether everyone sees the same price as the author of the model. I will make these available on the Shapeways site but haven't quite worked out what I need to do yet. I will probably also make the sprues a bit fatter to be on the safe side. I'll also try sitting some persons on them to see if they need any dimensional adjustments.

 

Regards, Andy

[D869]

I think I have now managed to make this orderable by other folks now. I must say that I found this a surprisingly puzzling process.

 

The model has been updated to make the sprues 1mm square so that hopefully the whole lot will stay together in the post. I also increased the seat back thickness by 0.1mm because what I got back was slightly thinner than I had drawn. Mine all arrived intact, but I'd rather play safe than have folks receive broken bits.

 

If you want to try these out then search for "coach seat" on Shapeways. If you use the quotes then you will see some relevant products. For some reason if you don't use quotes then you will see hundreds of things that have no obvious relevance to railway coaches. I have no idea why this is but if anyone knows then I'd like to know too.

 

One more thing that I don't understand is why the price that is shown from the search page is not the same as the price shown when I go into the model properties. All very puzzling, but I really need to stop fiddling on the Internet and get back to some actual modelling now.

 

If anybody does order some then please do let me know how you get on.

 

Regards, Andy

[Wild Boar Fell]

I think I have now managed to make this orderable by other folks now. I must say that I found this a surprisingly puzzling process.

 

The model has been updated to make the sprues 1mm square so that hopefully the whole lot will stay together in the post. I also increased the seat back thickness by 0.1mm because what I got back was slightly thinner than I had drawn. Mine all arrived intact, but I'd rather play safe than have folks receive broken bits.

 

If you want to try these out then search for "coach seat" on Shapeways. If you use the quotes then you will see some relevant products. For some reason if you don't use quotes then you will see hundreds of things that have no obvious relevance to railway coaches. I have no idea why this is but if anyone knows then I'd like to know too.

 

One more thing that I don't understand is why the price that is shown from the search page is not the same as the price shown when I go into the model properties. All very puzzling, but I really need to stop fiddling on the Internet and get back to some actual modelling now.

 

If anybody does order some then please do let me know how you get on.

 

Regards, Andy

Hello Andy,

Congratulations on your prints, they have worked well especially for a first attempt. I think the two prices that you mention are the price before VAT (When in Model Properties) and the higher (search page) is post VAT so will depend on where you live.

Hope this helps,

Regards,

Wild Boar Fell

[D869]

Hello Andy,

Congratulations on your prints, they have worked well especially for a first attempt. I think the two prices that you mention are the price before VAT (When in Model Properties) and the higher (search page) is post VAT so will depend on where you live.

Thanks. I'm pleased with the way they turned out and pleasantly surprised at the speed of the design and printing process compared to getting etches done. Having said that, the seats are very simple so comparing to the amount of CAD work needed to fill an A4 etch with 2mm scale bits is a bit unfair really.

 

You may well be correct on the VAT thing. Given that the prints are done in the Netherlands I'm not sure if we pay Dutch VAT or UK VAT but from memory, Dutch VAT is not a great deal different to ours.

 

Regards, Andy

[Etched Pixels]

You pay dutch VAT at 20% unless you are a UK VAT registered business in which case you'd not pay VAT but would charge it to your customers (and spend your entire life doing paperwork and feeding accountants).

 

The low price you see in the properties is the actual cost to you

The higher price with VAT is the cost to you including tax

 

For anyone else in the EU the cost will be the same, plus whatever you choose to add if anything in markup.

 

If someone in the USSA orders stuff I'm not sure how it looks tax wise as they also do stuff in New York .

 

Alan

[Nile]

I've discussed this before on the shapeways forum.I was told by a member of staff that we pay the UK rate of VAT (20%), which is just as well as the Dutch rate is now 21%.

http://www.vatlive.com/vat-rates/european-vat-rates/eu-vat-rates/