Translucent/transparent material

[Baz88]

Hi guys,

I'm building my first 3d printed model and I have 3 issues which i'm struggling with if any of you could help. I've tried to attempt this several moths ago, but never got the chance to do it, as i was trying to make it too difficult, so i've simplified it and kept the essential pieces. I was initially going to hollow out certain parts and run electrical wiring through them, but that proved difficult to do.

1. So i'm 3d printing a shell shaped roof for a large model, however, i have a bit of an issue. The shell is made up triangular panels, most of which are fine to print, however, a few of them are translucent with a grey tinge to it. They need to be translucent because i will install led's inside which will light up form the inside.

I'm wondering if anybody can give me advice as to how i can achieve this outcome.

http://www.steel.com.au/~/media/Blue...att.ashx?w=640
http://www.steel.com.au/~/media/Blue...nna-snape.ashx

2. I have one other issue and that is, as you can see from the photos, there is a black strip which runs in-between each triangular panel. These lines i will need to hand paint somehow, however, all the panels are the same thickness, creating a smooth surface and hand painting perfectly straight lines will be near impossible therefore, i am thinking about raising each of the panels, creating an indent, similar to a box gutter(that's actually what it is in real life) so i can paint inside that indent and it gives me a guide to work with. What i'd like to know, is in order for this to work, how thick would i need to raise the panels so that the 3d printing machine will do it properly? the 3rd image shows what i'm talking about.

http://design100.com/downloads/mda/1...dium_LED-1.jpg

3. The third issue is the seating. I am 3d printing the slab of the grandstand which is essentially a stair. Now the seats need to be green and when viewed front on all you can see are the green backs of the seats, however, there is a difference between the grey of the slab and the green of the seats. I don't want to paint the the vertical portion of the slab green cause that would look a little strange because it would be a horizontal strip of green, and you won't necessarily get the depth or the separation of each individual seat, so i was thinking of a grey slab and green seats, however, i'd rather not print 30,000 individual seats, firstly because when scaled down the seats will be to small to print(about 300m @1:1, meaning about 1mm wide at the scale i'm printing) and i would need to paint every one of those if i modelled and then printed everything as it is in real life. Essentially i want it to look as close to the 1:1 scale as possible without cutting corners which will be noticeable. so i'm quite stuck on how to approach this..

https://c1.staticflickr.com/7/6025/5...1d698ca3_b.jpg
https://www.australiandesignreview.c...-stadium-2.jpg

I hope that made sense.

I'm not sure why, but i don't seem to be able to attach images, so i have pasted in links to the images.

Would really love some help.

[ralphzoontjens]

Hi,

What 3D printers do you have access to?
A multimaterial polyjet machine would be perfect for this as you can achieve translucency by using small thicknesses (0.5-0.8mm) and gradations of grey by adding Tango black. If you are printing at 300:1 scale a polyjet model would be extremely expensive, at least over $2.000.

I suggest using Shapeways black strong and flexible material to create the structure without the paneling. Each triangular hole will need a flange and snap fit if you don't want to glue the panels in, for holding the panels. Then I suggest laser cutting the panels out of PET or acrylic sheet. You can achieve tints with colored foils, say car window films. Milliken is a supplier of transparent PP sheets which come in any color you like, it's called ClearTint. With acrylic sheets you can achieve translucency through sandblasting. Lexan works well for this too, it is sandable.

Printing the concrete slabs can simply be done with a FDM printer. There are PLA filaments available in specific concrete colors, check for example Faberdashery and http://treedfilaments.com/3d-printing-filaments/.

For the chairs I recommend SLS printing because of the detail and thinness of the part. I recommend to print all chairs in a section of the same color (they are mostly all connected) as one piece. So for each stadium section with 3 colors you will have 3 printed parts. If you print it in white, you can dye the parts individually. With different concentrations of the same dye (this looks like Kelly green) you can probably achieve all 3 colors. For the breaks in between the chairs, you can use a grey marker or small plastic strips afterwards. You could laser cut these strips together with the white panels, for example.

It will work really nicely. I have given this kind of advice many times, also for large automotive models and they came out very well.
Also details add a lot to the overall quality of the model - see if you can print tiny billboards and the scoreboard, for example. Add power LEDs to the stadium lights, etc.

[curious aardvark]

Umm, suggesting he use a bunch of services and industrial printers, probably isn't the answer he was looking for :-)
As well as being extremely expensive.

There are plenty of translucent coloured filaments around - check out the polymaker polyplus line, http://www.polymaker.com/shop/polypl...lucent-colour/
This stuff is excellent and ideal for printing parts with leds inside.

For your box gutter - I'd say half a mm depth should be fine.
Depending on the width of the 'gutter' you could simply print out narrow, black strips and glue them into the gutter.
Most well tuned fdm machines can do 0.8mm width. Make the gutter 1mm wide and you could simply glue it straight in.
If you used a flexible black material - I'd recommend polyflex. Then you could print long strips and just run them round the edges of the panels.

Seat wise, ralphs three section idea looks good.

Can't see any reason it can't all be easily done on an fdm printer - you just need the right materials :-)

[ralphzoontjens]

I agree, just using FDM printers for the most part you can create beautiful models and many times cheaper.
If it has to be accurate, you will need several different techniques. It depends on what the purpose of the model is.
For painting the frame I would rather have a protruded ridge than a gutter, it makes it easy to cleanly color the top surface just with a brush or marker.

[Baz88]

Thank you for your advice everyone.

I'm going to focus on the roof for now and there are a couple of options i'd love some advice on. Now i am going to run a test print, however, even the test print needs to be as close to perfect as possible due to the costs involved.

So what i've done is created a 1mm gap as suggested for the gutters and raised the triangular paneling and will run flexible black strips between them. Here i have 2 options, which i'd like to run past you.

1: I can print the structural frame and laser cut the triangles as first suggested and glue them in(Each triangle is only about 10mm though) or

2: Ideally i'd like to print everything as a whole, unless it is a significant cost saving and then just leave gaps for the clear panels which i can laser cut and then tint. Ideally, I'd use a multi jet printer, but i can't find anywhere which has one where i live.

Please keep in mind, that i have to print 20 of these shells with about 10 of those being a little larger than this one, which is about 80mm wide so costs is certainly an issue. I was quoted by one place for $45 to print in white resin so multiply that by 20 and you can see what i mean.


Now, the big issue. I've never 3d printed before, so i don't know what kind of material to use. I'd like everything to mainly be done using the same material, except for the clear triangle panels, for simplicity and cost. The options i've seen are: PLA plastic @ $3/15min, powder @$10/15min, resin @$16/15min or ABS plastic @$18/15min. I don't really like the look of the plastic used in lego for an architectural model, because it looks a little manufactured.

Given the size of each triangle panel (10mm) i really don't think i can create a snap and flange that small and will need to glue them in or use a multijet printer if i can find one.