Using RepRap to help the blind

Hi Everybody

My name is Bob. I’m a mechanical engineering student in Boston, MA and I do some ME consulting work for the National Braille Press. What’s the NBP? They print (emboss) all kinds of braille publications -- including magazines, books, newspapers and even standardized tests and textbooks for the blind.

Besides the Braille text itself, the NBP is also responsible for recreating images in a form the visually impaired can feel and extract information from; these are called “tactile diagrams.” This is especially important in textbooks and standardized tests where students rely on graphs and other visual information essential to the content.

Currently, tactile diagrams are made by the “collage” method. A tactile diagram maker will use the original image as a reference and build up the image by hand using foil, paper, string and other materials. This master mold can then be thermoformed over to create multiple tactile diagrams. The problem with this process is it is time consuming, labor intensive and master molds are hard to archive.

We’re trying to update the process. The idea is to scan in (or redraw) images on a computer and then 3D print a master mold than can be thermoformed over. This will allow for better tactile image quality, streamlined diagram design and the ability to digitally archive master molds as .STL files.

I’ve created a sample of Braille with tactile diagram features and printed it using a commercial Dimension 1200ES FDM printer and thermoformed the result (see pictures: 3D print is photo2 and thermoformed copy is photo1). The results are very promising, but this was a commercial FDM printer. To help make this process as low cost as possible (schools for the blind don’t have extra $20,000 laying around) we want to see if RepRap (or RepStrap) printers can achieve the same (or acceptable) results. The NBP is considering an Ultimaker for initial testing, but we'd like to see if the print quality is fine enough to handle braille details.

If you'd like to help out let me know and I'll send you the .STL file of the Braille sample in the picture for you to print. It would be great to see one printed on an Ultimaker, Prusa or any other. The sample is 10 x 10 cm and is less than 2 mm thick.

Thanks in advance from me and the NBP!

Bob

Edited 3 time(s). Last edit at 01/21/2012 02:11PM by rhertig.

Bob,

I sent a link to this forum page off to my sister in law, who is a Braille translator, and who has asked me the same sorts of questions. I just built an Orca v0.3, and am in the process of calibrating it... which I understand may take a while. Once I have it dialed in, I'll give your print a shot.

David

there are several raised text and braille objects and modules on thingiverse if you would like to look at them.
[www.thingiverse.com]
[www.thingiverse.com]
[www.thingiverse.com]
[www.thingiverse.com]

there are also a few openscad scripts that can take a picture and automagicaly convert it into a height map

I hope some of this is helpful to you

Thanks, that would be great. I've attached the .STL here for anyone to try, let me know if you get good results.

The first (not so good) news is that this needs more detailed features than the standard 0.5 mm nozzle can do. You'll need someone with a 0.35 or 0.25 (whatever is tinier than your littlest feature) nozzle hot end to test it.

Yes you need to tune the image to the printer. I sliced the file using Skeinforge with a layer thickness of .33mm and the fourth layer is per the attached. The print was identical. So in order to see if your file is printable, all you really have to do is slice the STL file. Keep in mind that nozzles do very so .33 is not universal, and the finer the nozzle the better the resolution but the longer the print time. My impression is that most of this is printable, however some of the fine vertical lines in the lower left may not print. One more observation is that the third layer just below the dots is a bit rough, so even though you can see the dots, I don't know how easy they will be to read by touch.

I'm curious whether the printed Braille and tactile diagram objects hold up under the temperatures and pressures in the thermoforming process. How do thermoforming temperatures compare to the temperatures used in these 3D printers?

Edited 1 time(s). Last edit at 01/22/2012 03:00PM by Paul371.

@Dean448

Thanks for the information and insight, i'm going to begin slicing some diagrams to see if they're printable.

@Paul371

That's a good thought, but it seems like the thermoplastics used in 3D printers hold up fine when thermoformed over. I thermoformed over the Braille sample i have (FDM -- ABS) and the features transferred to the thermoform Braille paper very nicely with no apparent melting or damage to the 3D printed orginal. Also, i've read that thermoforming over FDM (or FFF) printed parts is a somewhat established process that people are doing so that aspect should be okay.

I'll do this tomorrow! It should be no problem.

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www.Fablicator.com

I made some lithophanes a while back on a small CNC, the software may be usefull to do what you want, the resolution may be better than a 3d print, I can do a sample if it helps.

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Random Precision

As much as I hate to admit it (because I love 3d printing), I think johnrpm may have a point. A small CNC mill will probably be able to make these simple designs MUCH faster, more precisely, and and less expensively than any 3d printer in existence.

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www.Fablicator.com

It printed pretty well on my stock .2mm layer settings, though the 5th down line on the left didn't seem to be there.

[i211.photobucket.com]

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www.Fablicator.com

Thanks for the print Andrew, it looks really good. You make a good argument for CNC mill, but I really think 3D printing has its advantages that make it worth exploring. One advantage being that FDM or FFF plastic models are naturally porous and makes them perfect for high detail thermoforming (the machine pulls a vacuum through the model).

I'm trying to minimize the time and material needed to 3D print these features by using a porous platform that each graphic will be printed on. That way excess time/material isn't wasted on the 1 mm X 100 mm X 100 mm square foundation.

thanks again!

bob

Probably the best way to do it is to have the square be ~2 layers thick (.4mm.) Should be enough to support things and only take 15min to make.

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www.Fablicator.com

Embossing stamps come to mind, they engrave a small block with your name etc, then for the other half pour something like low melt alloy, the blocks are mounted in a small press and letters can be embossed directly into the paper.

A larger version of the above may work well, I know you want to persue the 3dp avenue and it may turn out OK, but I asked
someone who works in a library here in the UK if they had heard of this type of image for the blind, they had not, maybe its a specialised thing, but a worthy cause to look into and a good use of my machine.

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Random Precision