Laser etching PCBs update. DO bother. It's awesome

After a successful evening etching circuit boards at BuildBrighton last night, Steve insisted on issuing a retraction to a statement made earlier this year: creating etching masks for PCBs with a laser cutter can be a quicker and easier than using press-n-peel - especially for enormous great big boards.

So why were we eching A4 sized circuit boards at 10pm last night anyway?
We'd already decided that a custom-made PCB was the way forward with our board game idea - now it was time to prove it!

Using full A4 sheets of press-n-peel was a non-starter: with so much ink on the board, getting a consistent, clean etch would be almost impossible - as a large quantity of toner melts, the entire blue sheet starts to float on a great big puddle of liquid ink, resulting in blurred traces and smudged filled planes with just the tiniest bit of movement during the heat transfer. We've done A5 sized boards before now, using press-n-peel, and may one in three worked well enough to get a clean etch. Trying to effectively make four of these boards in  one go just seemed like trouble! So it was time to give lasering another go...

We used the same Halfords Matt Black car paint as before and set the BB laser cutter into action. It took about 30 minutes to fully etch the paint off a full A4 sized copper clad board:

The important step that we'd missed last time, was giving the board a generous wipe over with some white spirit, to clear away the vapourised paint off the exposed copper tracks. Cleaning the board thoroughly before etching allowed the ferric chloride to work much more quickly on the copper. Also unlike last time, we used a PCB etching tank, complete with heated ferric chloride and an aerator (bubbler) to help improve etching times (and remove spent ferric off the surface of the board, without having to constantly dip the board in and out of the brown sludge)

The result was a pretty impressive, super-sized PCB (the edges have yet to be cut to size, but that's a job for once everything else is in place.

We did consider making a double-sided pcb, but lining up two sets of traces on one single board, with so many vias (this board has about 94 vias) seems quite tricky. Normally on a homebrew double-sided board there are three or four places where getting things lined up is critical, so you can use large pages and give yourself a little bit of "wriggle room" should things slip slightly. But because we couldn't be exactly certain of getting the laser to etch the opposite side in exactly the right place on the reverse (and because it takes so long to etch) we decided to make a separate pcb out of much thinner copper board and simply glue it to the underside of this board, once aligned in a few places.

Our thinner copper board wasn't quite A4 sized, so we put two sheets together and made sure the join was nowhere critical in the top layer design. Then it was time to set the laser going and discuss the days events over a brew - it would be another 30 minutes before the next board would be ready!

With the second boards cleaned, and dipped in the ferric chloride, we pretty soon had all our copper etched and ready for drilling.

checking the etch quality by holding the board up to a bright light - any non-etched or badly etched parts would be easily visible.

The question now was whether everything lined up correctly!
The PIC microcontroller sat in the right place and lined up with it's own pads, so things were looking quite promising to begin with...

So now it was time to put the boards together and see if the whole idea actually worked. Obviously drilling the boards separately would be time consuming, so we thought it best to place a couple of pins in  opposite corners and get the boards lined up, back to back, then drill through both layers, at the same time, for each pad.

The few locating pins lined up beautifully on both sides of the board (one pin was about 0.5mm out but that's a level of deviation we can work with, on 2mm pads). The boards were pressed firmly together and the pins soldered on the underside.

The resulting board is starting to look very promising indeed.
In the photo you can see the hand drill used. Originally we put a 1mm bit into a Dremel, but this does tend to grab a bit when drilling. Because we don't want even the slighted bit of deviation from the centre of each hole (to give us the best chance of hitting a usable part of the pad on the other side) we resorted to drilling each hole by hand.

With 88 squares (it's an 11" x 8" board) and a few extra power/connector vias, there are a total of 96 vias on this game board. So far we've drilled six. Tomorrow night's BuildBrighton meet-up is going to involve a lot of drilling!

Digital board game - time to get serious

After spending hours and hours working on our digital board game, we've come to the conclusion that we're going to need some help getting a robust, working two-layer board.
So far we've tried to concentrate on:
a) a board that can be built cheaply using easily sourced components
b) a board that can be manufactured quickly and easily by anyone with no specific skill requirement.

To date we've managed the first, but failed miserably on the second.
We tried using copper tape to make a keypad membrane, but it was far too fiddly to lay down consistently well enough to be robust. So in an attempt to make it more robust, yet keep it easy to manufacture, we knocked up a prototype using conductive ink (one of those silver pens from Maplin). The pens are quite expensive, so we've blown the first requirement of making our boards - but for now we're concentrating on addressing the second!

We drew the "switches" as two halves of a touch-to-make switch. After drawing the conductive traces, we placed a paper separator layer on top. Finally we stuck a top layer on with bits of copper tape to bridge the two halves of the switch, when pressed.

During testing this worked fine, but only when the buttons were pressed by hand. Because the board is copper, not ferric-based, our neodymium magnets are not attracted to it. So we tried sticking some steel nuts to the underside of the board. Our only question was whether or not the magnet would be strong enough to be attracted to the nuts, through the thickness of the copper PCB board (about 1.6mm) ?

It turns out that the magnet is plenty strong enough! There was quite a pull between the magnet and the playing surface. So we did some testing using our fully printed (and plastic laminated) top layer.

here you can see the resistance across the switch is measured at about 13 ohms when closed by the magnet, which is attracted to the nut glued to the underside of the copper board

By a bizarre coincidence, the height of our steel nut raises the top of the copper board to be exactly flush to the top of  a sheet of 5mm thick foam-core FoamEx board.

So with this in mind, our current plan for making the electronic board game sections is to have a PCB made by a professional manufacturer and use some steel (it may even be regular nuts and bolts!) on the underside of the board. The PCB could be edged using FoamEx (or maybe some 5mm acrylic) to give it a finished look, and the top, printed layer, could be glued over the whole thing, covering the joining edges.

Professional manufacturers prefer to work with Gerber files, and our favoured ExpressPCB is only good for making toner-transfer images as PDF files - it doesn't really export the final PCB layer in any format - so we downloaded and installed a previously tried PCB program: DipTrace.

For 30 days, DipTrace is fully featured (you can download a 300-pin-limited free, non-commercial version) so we've got a couple of weeks to try this out and see if it works. DipTrace is actually a really neat suite of programs for making PCBs - we might even go crazy and spend some serious money on getting a full licence once this project is out of the way!

After a few hours of shifting traces around, we managed to make an 11x8 keypad matrix on an A4 sheet. Impressively, DipTrace has a 3d model viewer, to see how your PCB will look once assembled:

Our board is pretty basic. We've used "fingered" touch-switches on the top surface (each half of the two-part switch is interleaved and the printed playing layer on top will have conductive dots under each square on the board) which are routed to a series of pins on a PIC 16F722 on the underside. The notches on the edges of the board will house tiny 3mm magnets which we'll use to connect the edges of each board section to the next one.

The advantage of the PCB-based approach (we originally started off like this, and gave up in favour of a "cheaper" alternative many months ago) is that each board section will be good and robust. It also means that we won't have to mess about with micro-wires, taking the traces from the copper-track-switches to a custom PCB on the underside - since each board section will effectively just be one big PCB, it means that assembly will involve soldering a single 28-pin SOIC chip and sticking a few magnets with some no-solder conductive glue.

With the PCB already designed, all we need to do is find a manufacturing house with a fast turnaround, so we can give the idea a go!

3d printing miniatures at the TCT Show

The TCT Show had all kinds of amazing 3d printers, with everything from the aeronautics to the hobby market represented. While a lot of the show concerned enormous, super-expensive, metallic powder sintering monster machines, there were also a few smaller-scale printers and some rather interesting print-bureau services on offer too.

One of the more ingenious 3d printers was from mCor and instead of using expensive metal powder, or difficult to handle plastics, it used readily available - and cheap - printer material: paper!

The printer was like an xy vinyl plotter with a rising bed: a sheet of pre-printed paper was loaded onto the bed and the drag knife cut out the outine of the pre-printed shape. The head then applied a series of micro-dots of glue over the layer and pulled a second sheet on top. After this, the bed rose up (pressing the two sheets of paper together) and then dropped down again before the cutting head cut through the second sheet of paper.

By exposing the printed edges of each layer, a full-colour, 0.1mm accurate, 3d model came straight off the machine. As this kind of technology becomes popular, expect plenty more "3d-wedding" photos in future:

One of the nice things about the models off this 3d printer was that they had substance. A lot of times, 3d printed models feel a bit light-weight and flimsy, because the printer is trying to use the minimum amount of (relatively expensive) printing material. With this printer, each model has the same density as wood or mdf. For the models at the show, some were coated with superglue (to seal the edges) which made them very hard-wearing and robust.

The mCor paper 3d printer is an excellent layer-based full-colour 3d printer!

Throughout the afternoon, the inhouse band played along on their 3d printed guitars. We agreed that their "phat tunez" weren't much to write home about, but the actual instruments looked amazing

a complex internal structure was revealed through the stars and stripes of the guitar body

noted for their powerful sustain, thanks to a dense solid wood body, this Gibson Les Paul-a-like might not sound as good, but it looked pretty cool

There were lots of laser-sintering printers on show, many demonstrating the wide range of colours that could be used for printing. Many 3d printers demonstrated how complex and intricate their designs could be. The lasered pieces looked really nice - but when you looked beyond the complex structure, the final finish was still not quite glassy-smooth (though very impressive, all the same!)

There were quite a few companies offering print bureau services. This means that instead of paying tens or hundreds of thousands of pounds for a printer, you could simply email them your 3d objects and have the printed item posted back - a service similar to Shapeways or Ponoko; it's nice to know that there are so many alternatives, and interesting to see the many different finishes available, based on the machine doing the printing.

One printing company that looked particularly interesting was Luma3d print, who were offering laser 3d printing from 10p per square centimetre (cm3). This looked like a really interesting way of getting relatively cheap, relatively good standard, master shapes for mould-making, without breaking the bank.
Their models still had the slightly grainy appearance of most laser-sinter printed objects, but they can print from ABS which, apparently, can be sanded and polished to a really high gloss finish.

Interestingly, there were a few companies demonstrating the quality of their 3d printers by printing war gaming miniatures. There were two or three of particular note:

Solidscape were the first company we spotted with miniatures in their display cases

This little monster was smaller than the GW standard 28mm miniatures, yet had some incredible detail on it:

The Envisontec printer apparently used a wax-based compound and is commonly used in dental practices for prototyping sets of gnashers!

Their miniatures were incredibly detailed with no discernible "banding" or layering as often seen, even on the best laser-sintered objects

Envisontec were another company demonstrating 3d-printed miniatures. Even at the smallest size (the miniature on the right is smaller than the 28mm tabletop standard) the details were pretty amazing.

If anything, the details from this printer were even better than the previous one. This insanely small galleon has rigging on it, less than 10 microns thick. This whole model is smaller than the size of a fingernail!

Towards the end of the show, we got to speak with Gary Miller from IPFL who had some dinosaur heads with the tiniest little teeth imaginable to come off a 3d printer!

Gary went on to explain that his company produced many of the master models for Games Workshop miniatures, and had re-trained many of the GW sculptors into using ZBrush and similar virtual modelling tools, to produce their latest model lines. Maybe this explains why only recently we were asking why Citadel/GW miniatures were of much better quality than many of their rivals!

The print quality of the dinosaur teeth was unbelievable. Their printing can produce models with layers just 6 microns thick.

Interestingly, IPFL offer bureau printing services and Gary explained that an average-sized GW miniature would cost about £25 for printing. Only up until very recently did GW have all their miniatures printed by an outside agency - until they saved up enough, I guess, and bought one of these very printers themselves!

It seems that designing your own characters in CAD and using a 3d printing bureau has actually become a viable method of producing your own miniatures - even a relatively small production run could quickly cover the cost of printing and casting materials. Perhaps this is why we're seeing an explosion in miniature-based games on Kickstarter of late!

Of course, the busiest stand at the whole show was the RepRap stand (or, as some wags described it, Hobby Corner)

The RepRap and RepRap pro were on hand to give demonstrations and were busy printing keyrings and trinkets for people to take away. Disappointingly, there was no-one selling the more exotic abs/pla filament. There were some interesting colours and peculiar effects on display, so it was a shame they couldn't be bought there and then. Though Steve did manage to blag some samples of metallic gold and electric blue filament, so hopefully he'll be able to print some demo objects on his RepRap at home and bring them along to BuildBrighton tonight......

Army Painter Quickshade results

Army Painter Quickshade is a great way of getting details on miniatures to stand out and get them to a half-decent standard very quickly. As well as adding shade to the creases and crevices, it also "tones down" the whole model quite a bit. So as a result, you need to be quite careful about your choice of colours for the base coats.

Here's a Tyranid base-coated white and shaded using Quickshade. Note how the bright white has become a skeleton-bone colour - perfect for these models, but not necessarily an effect you'd want every time.

Other colours are similarly muted after being Quickshaded - so our Tyranids look rather colourful to begin with

undecided on a colour scheme, we thought we'd try a few and see which looked best at the end!

After applying the Quickshade the results are quite different:

Of them all, the red one is our least favourite, but best-shaded model. Colours with a blue element (blues, purples, slate-grey etc.) don't look brilliant with Quickshade, because of the slightly brown tinge. Maybe the blue Tyranid will be ok once the anti-shine matt varnish has been applied and the blue colours "picked up" again with a few edge highlights.

The purple miniature doesn't look quite as good as the earlier one for some reason. A few people have suggested it's something to do with the colour wheel - the earlier model had a more yellow-y tint to the bone colour, which - apparently - is a more complimentary colour to purple than the paler white-based model. I can't pretend to understand: to me it's like hearing a bum note in music - I don't know what the right one is, but I can definitely tell when something's wrong!

I think I need a few more lessons on understanding the colour wheel. Here are a couple more miniatures painted up over the weekend. The painting isn't too bad (it's in all the right places) the Quickshade really brings out the details, but there's something just not quite there with them - they look ok. But only ok, not amazing...

whacking the base colours on takes less than an hour using the Army Painter approach - no need to mess about with highlights, just get the (sometimes over-bright) base colours on in the right places, and keep faith in the brown gloopy stuff

Quickshade really brings out all the details in the models, as well as adding a bit of "life" to clothing. Where possible we tried to stick to no more than two or three colours per miniature

The soldier on the left is almost ready as is. The guy on the right needs a bit more work to bring out all the tiny little details on his face. To get a miniature to this level would usually take about 4-5 hours of layered painting. These two (and two others) were painted to this level, from undercoated, in about two hours - that's about thirty minutes per model!

We tried to keep to just two or three colours per model. It's tempting to go crazy and stick a bit of colour everywhere - there's no doubt that Quickshade tones down a model a lot, and the immediately obvious way to counter this is to use lots of bright colours. But multi-coloured models look a nightmare on the tabletop, so it's just a matter of finding out which combinations of colours look good after they've been shaded.

Hopefully we can make these minis look good again when they've been matt coated and the tiny details have been picked out to give them a bit more visual interest.

We're not going to make the same mistake as last time - these miniatures will have to wait until Wednesday night before they get a coat of anti-shine. In the meantime, we're going to experiment a bit more with colour combinations, to find out what works (and hopefully learn to stay away from what doesn't).

Army Painter display stand in MDF

After an unusually productive evening at BuildBrighton last night, we're pleased to share plans for our Army Painter paint pots stand:

Here are the SVG files - load these into Inkscrape and save as whichever format best suits your laser cutter (or the laser cutter at your local hackspace!). We used the BuildBrighton "white laser" which runs off RetinaEngrave - a virtual printer, so could just print these straight from inkscape, but  also successfully saved as .dxf and can them on the "red laser" - an HPC 3020 hobby cutter.

Obviously we designed this stand for our Army Painter paints but will work for any dropper style bottle, up to 25mm across and 80mm high  (a few others have already shown a renewed interest in miniature painting and have also got a set - or partial set - of similar paints).

To make this stand, you'll need three sheets of A4 mdf (or acrylic).
If using mdf, the cost of materials works out at about £1.50 (we buy our medite/laser mdf in bulk, in sheets and an A4 sheet works out at less than 50p). This is a massive saving on some of the laser-cut stands on eBay which sell for £20-£30!

Tops - you need two of these per paint pot stand:
https://docs.google.com/file/d/0B9HAI5y47e_WNFcxZnVJem9idHM/edit?usp=sharing

Sides - you need one of these
https://docs.google.com/file/d/0B9HAI5y47e_WSzljeEkxc1V2Wms/edit?usp=sharing

Assembly should be straightforward - the top sit on each "step" of the sides, there's a bracing strut across the front of the bottom step, two struts at the top and bottom of the back and the last strut goes under the pots on the bottom step (our first version didn't have this, and when you lifted the whole stand, the first row of paints still sat on the table!)

We used PVA glue to hold everything together. You can use Superglue for "instant grab" while assembling, but we liked that PVA gives a bit of wiggle-room to slide everything properly into place.

How to ruin a miniature with anti-shine

Yesterday morning, almost as soon as the postie had delivered the Army Painter Quickshade, I slapped some onto an alien miniature. Despite being a really basic paintjob (flesh painted a bone colour, carapaces painted purple and that was it) the Quickshade picked out all the details perfectly. Even the non-painting nerds started showing a bit of interest, as the results were so impressive!

I love the effect. Nice deep highlights, the almost "cartoon-y" look but plenty of super-fine detail makes the paint job look far better than it is. So this morning, after waiting the recommended 24 hours to allow the varnish to fully dry, I applied a quick coat of Army Painter anti-shine matt varnish.
The result wasn't quite what I was expecting:

All the lovely details have become a cloudy, grey gloopy mess! There's even a nasty crackling effect on the larger flat areas (like along the tail). Either there's something wrong with the spray varnish, or the way I applied it - my latex gloves were covered in sticky scales of congealed anti-shine varnish:

And on the metal minaitures, the effect was even worse! The matt varnish has managed to strip away parts of the quickshade varnish (in the photo below, you can see that on the solider's right leg  -on the left of the image- part of the underlying base coat is showing through)

What started out as an exciting new way of painting miniatures looks like a quick way of assigning them to the bin! I can't imagine that the plastic Tyranid alien is salvageable (paint strippers are likely to melt the plastic). Maybe some Mangers Paint and Varnish remover will restore the metal soliders as it did our Blood Bowl Orks a few years back. Or maybe, since discovering the sculpting inadequacies on these miniatures, I might just pop down to the local GW store and pick up some plastic soldier-looking miniatures?

After all, the plastic Tyranid alien looks great when painted up and shaded with Quickshade - the details really stand out far better than the details on these metal soldiers - I just need to find out how to finish them properly, without ruining them!

Do Games Workshop and Citadel really make the best miniatures?

It's something I've never considered before (it's taken a long time to get any of the other nerds to admit to even being interested in miniature painting, let alone being passionate about it enough to express an opinion on, so maybe I'm on my own here) but there are loads of miniatures manufacturers "out there". And with easy online ordering, there's plenty of opportunity to compete with the dominant retail outlet Games Workshop.

So why are Games Workshop miniatures so popular, and so in demand (certainly in demand enough to command stupid prices for badly-painted second hand examples of their work on eBay) when there are plenty of cheaper alternatives?

A little while back, we got hold of some Mantic miniatures - when I was trying to explain to everyone what a great idea for a game Dreadball was. To be frank, they are awful. Then we got hold of some metal soldiers (can't remember where from, nor how much they were). These are the miniatures I've been painting to try out the Army Painter Mega Set and QuickShade.

On first sight, these are some pretty nice miniatures. But as I've been painting them, I've been a little disappointed by the finishing on some of the details. Where the fingers wrap around the gun handle, for example, the fingers just stop against a blob of some rough filler shape between the arm and the body of the miniature.

It's difficult to photograph, because you need to view the miniature from different angles to spot the problem - but here's another example of poor finishing on these miniatures:

See how the bottom of the equipment hanging off the belt hasn't been finished off - you can even see marks on the base of the packs where the modeller has been shaping his clay!

These aren't major issues - they're not going to stop me using these soliders for the promotional material for our Starship Raiders game - but just examples of the difference in quality of different miniature manufacturers.

The Games Workshop miniatures, on the other hand, are excellent, from every angle. Even in hard-to-reach-places, and areas that are almost never going to be seen, the quality of the sculpting is as good as anywhere else on the model

Even under the body, where it would never been seen without really close inspection, the level of detail on the GW Tyranid is consistently good across the whole of the miniature.

When I started looking into restarting my old miniature painting hobby, after a 20+ year hiatus, I read a lot about how plastic was the default material, and how the miniatures today are not as good as the lead/pewter ones of times past.

As much as I begrudge paying GW prices (of £3-£4 per miniature in a boxed set of multiple models) for a few bits of injection moulded plastic, I can't help but think that there is some justification in their prices - cheaper miniatures - whether made from plastic or metal - can be of much lesser quality.

I can't believe that I've gone from a know-nothing to an uber-miniatures geek in a few short days. And many of my opinions may be discredited in a few months from now, as I learn more about the hobby in general. But from now on, I'm sticking with GW/Citadel until someone can demonstrate a better range of miniatures - in both quality and price.