SLA 3D Printer Log 1: Projection, Projection...

In between dreaming of a house where model trains bring me pre-mixed Robinson's squash and keenly observing the cathartic tidal wave of backlash against Dungeon Keeper Mobile I have received a 720p projector from Ebay, costing £250.  Before launching into the specifics of how to use it, let's examine the unit itself.

The book is A4 width (and 2cm shorter lengthways) for comparison, and the unit weighs 1.13kg

The unit is actually 206 x 162 x 75mm (lxwxh), feels like a quality implementation despite it's low weight and is highly intuitive to operate; this isn't surprising when we learn that this model (Nobo X22PW) is simply a rebranded Optoma TW330, which is going for £410 at time of writing.  That is excellent value for money given that most projectors in that range will be 1024x768 native at most, not 1280x800 native (keep an eye out for native resolution, most projector sellers claim their model will "handle" 1080p, but this is done through upscaling and will make your movie look anything but sharp).

*Review Interlude*

The unit is surprisingly quiet in spite of the fan having to keep a 2200 lumen lamp from exploding (not a hint of facetious here), and that lamp gives plenty of brightness even on std-mode with 1700 lumens.  It is audible, but it quickly fades away during gaming since the noise has no irritating frequency (that goes out the window in bright mode, I suggest just turning up the brightness in windows).  Having played Medal of Honor: Airborne on it I can say that it eco-mode might not be to everyone's taste but with lamps costing around £90 I think most can sacrifice 29% brightness for 66% more lamp life.  This is also a Single-Chip DLP model so it suffers from a little colour separation during fast motion (highly noticeable when you shake your head viewing a black background); finally I would like a better contrast ratio than 2000:1 for more defined extremes in the colours, but I'm rapidly disappearing down a rabbit hole here.

*End Review Interlude*

Back to the point at hand, 1280x800 will allow for a detail level of 0.1mm per pixel for a build area of 12.8cm x 8.0cm; I'm looking for a minimum resolution of 0.05mm seeing as I design for FUD on Shapeways (0.1mm Resolution), giving a build area of 6.4cm x 4.0cm.  One of my ideas up to this point was to traverse the projector along a vertical rail, utilizing a redundant RAMPS axis to adjust the build area/resolution balance, but I forgot to account for projector focus; what's worse is that the minimum distance I could get the projector to focus was around 28cm, which gives an image of 197.5mm x 124mm - well above the 64mm x 40mm required.

Despite this, the brightness of the resultant screen area was highly encouraging.

In order to attain this build area, I need to add an adjustable lens with at least 3.0x magnification.  DSLR lenses can be had used for around £50, given that a UV filter is a common accessory it may be that the lens can transmit UV without hindrance, but apparently DSLRs have UV filters of their own and there may be some in the lens too - an optical testbed will be required to fully investigate the matter, as well as some actual 3D resins (no VOCs, please).

Free Ideas Bucket 1.0

I intend this project to be completely open-source, that means any and all STLs and diagrams related to the build will be available royalty-free and not on my Shapeways Shop; if *you* would like to sell it, go ahead but be prepared for a hard time making money given that the models are free and Shapeways can be used by a Bonobo.  Anyhoo, I present my current list of ideas:

• A standalone built-in computer, either a Raspberry Pi, it's more powerful compatibles or even a full-on x86 PC.  This is to allow the printer to run without having to keep either my PC or Laptop running with it all night.
• An ultrasound sensor to detect the resin level in the bath and adjust the build platform starting point to suit, this is only relevant to top-down designs.
• A touchscreen on top of the machine, adjustable to either face outwards (for desk use) or upwards (for floor use).
• Gullwing doors...  just because...

That concludes the first of hopefully many buildlogs to the SLA 3D Printer Project.  The ultimate aim is to largely free me from having to use Shapeways for every.  single.  solitary.  step.  in the R&D Process for Tawe_TMD.  It's always the way when you make something that you trip up on things you couldn't have predicted, but even if I flounder and fail, I can always watch Zero Punctuation across my wall.

SLA 3D Printer Log 0: Sirens of the 1080p screen, and the prints of reason.

As far as temptation goes, getting a new PC is up there with crisps positioned but a few feet away after 3 hours of CAD.  I say temptation because my current aim (and New Year's Resolution mind you) is to be able to subsist upon my own business alone - not to have to rely on a job to pay my bills.  I have already made inroads towards this with my Shapeways Shop Tawe_TMD but I've hit a snag:  Research and Development.

I am currently developing my first proper product, which is a Metropolitan Ex-Twin Brake Van from the turn of the century in N gauge (1:148); the body is pretty much sorted out, pending any minor alterations for functionality.  The chassis also pretty much looks like the final iteration, so the bulk of the work is now done leaving me with the R&D associated with functionality - and boy was I in for a ride!

Each one of those strips on the side is 0.1mm high by 0.25mm wide.

In the UK it takes around 3 weeks from order to delivery, in the latter stages of R&D (tweaking) this holds true even for minor changes like increasing the distance between the axle holes; this is doubly frustrating when a mistake is made, such as an item being wrongly printed, this being the direct inspiration for this post and the potential project I will get to in a moment.  Shapeways solved this issue with haste and care and I applaud them for such attention, however, I consider it a call to action for a proper solution.

That solution is my very own SLA (Photo Lithography) 3D Printer; this isn't as difficult as it sounds, because according to many Youtube videos and This Instructable, it is entirely possible to print a 3D object using nothing more than a Z-carriage, a beaker of resin and a DLP Projector.  Feature sizes can be minute, too:  a 1280 x 800 DLP projector (£250 from Ebay) can result in objects up to 12.8 x 8 cm in size with a resolution of 0.1mm in the X and Y; you can even get higher resolutions simply by reducing the distance between the Projector and the resin (e.g:  6.4 x 4 cm with and XY res of 0.05mm).

I have made a not-terribly-professional case study into this idea and found some interesting facets to the idea of running a 3D printer like this:

I was never noted for relishing writing novels...

For the record, here's some additional information for those looking to check all this out (I did this on many assumptions):

• 1 Metro Brake Van = 2656 mm³
• I set a budget of £200 for materials, this includes minor electronic items like stepper motors, and any 3D prints for special parts.
• I don't know what I will coat the build platform with, but it will need to hold things during printing whilst peeling off when done.
• I assume Council Tax to be included with the Rent.
• Food + Taxes is broken down thus:

1. Food = £30/week or £120/month
2. Income Tax = £38.12/week or £165.19/month from here (assuming gross earnings of £15,000 a year)
3. The rest is for other things like electricity, gas, water which I can't be stuffed to calculate, but the remaining £164.81 should cover it

• As for printing, I am assuming a perfect run of setting up supports (SLA prints need copious support material, maybe not in the case of the Metro Brake but I'll apportion it anyway), a successful print owing to a reliable non-stick application (that's what the Sylgard 184 is for - It stops the print from adhering to the resin basin in bottom-up designs), and finally a flawless post-processing run (fat chance...).

It is quite clear to me that running this printer to print Metro Brake Vans to sell is not a viable proposition - even with sufficient resolution, the time spent in preparation will ensure absolutely no free time, an unacceptable situation when this business is intended to help me achieve financial freedom.  3 hours per print sounds low compared to 3 weeks, but remember that Shapeways is taking on all the work in those weeks, and I am free to make new designs while my Metro Brake goes on sale.  This printer makes much more sense for Functional Testing, i.e:  making minor changes around the coupling area or testing strengthening ribs.

To any aspiring Shapies, I say this:  If you have passionate pride in your work, be prepared to test and test and test - go so far as to intentionally break your redundant testing models to reveal weaknesses.  On the note of final presentation, don't be like many of the modellers on this virtual superstore of human creativity and only upload the STL with some token renders; this really shouts "That'll do, next!", and is that the attitude you would tolerate from a carpenter?  An engineer?  A NEST team?  One of the best ways of showing that you have done such testing is to upload a Youtube video that will show it running.

I hope that PC temptation doesn't get the better of me...

Introduction to Tawe TMD

Hello, my name is Stephen Sparey (B1t5yn8tr is my online name, also a blog which is not necessarily safe for work detailing my more general exploits).  I am the one-man head of Tawe TMD, an operation that derives it's name from the Tawe Valley, in which lies Swansea and the University I got my Foundation Degree at.

This blog is intended to provide a dedicated outlet for my operations specific to Tawe TMD; Facebook is very limited in terms of what it can display, only one image is permitted per post which is severely curtailing in terms of explanation.  I would also like to separate this material from my main blog in order to allow people to view the progress on my SLA 3D Printer without risking NSFW material showing up (I'm no angel by any stretch of the word); I predict some people will view it at work to kill the last 10 minutes.

I will add a link to my main blog for those who seek demented experiments (like making a Graphics card cooling shroud out of paper, that didn't end with dignity...), All SLA 3D Printer posts from there will be moved to this site, as well as a few Tawe TMD related posts.