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...