G3 Clubroom

The Forum for Gauge 3 Model Trains

Ok... Having consulted with a few others I have taken the decision to buy a laser etcher. This will allow me to produce my own plates and badges for locos and rolling stock.

I intend to use the laser to cut through an "etch resist" layer on a thin sheet of brass, and use Ferric Chloride to cut into the metal. (Yes I made a lot of my own PCBs as a teenager).

Regards

Ralph

Yes, as many people have guessed I LOVE "Goldfinger". My researches have turned up a company called "Trotec" in Tyne&Wear, they sell what could be my base material for making my plates with. This is a dual layer material in either plastic or metal. The idea is that you laser off the top layer revealing the lower substrate. This has MANY colour combinations  to play with -thus making a white lettered plaque on a black background is dead easy.

The laser has a "print" area of A5, which is ample for a few plaques. However the sheets of material only seem to come in 1200 x 600mm (!)

regards

ralph

This was a favourite concept for making labels in industry in earlier years, but it was a more rigid, 'Formica'-like laminates that were physically engraved to reveal the contrast.  I forget it's name, someone will know.  However the reason for writing is to support your concept and a suggestion to choose something like dark (or black) material with white skin.  That way the sign background can be painted the desired colour after lasering.
Rgds, Tim

Traffolite?

Yes!  That's it. Thanks Mike.

The final part of the system has been installed thanks to the work of IanT. The laser cuts holes in worktops and kitchen table tops with ease! The software is going to be trialled over the weekend. But first I need to build a small clamping table for it to hold the pieces in position while the laser fires.

Wherever possible I have used GNU software. So it will cost nothing to buy the software.

Regards

Ralph

All I did was listen sympathetically Ralph - you worked it all out for yourself in the end - so well done.

PS - Should we change your nom de plume from 'Cabbage' to 'Goldfinger'?   

IanT

You are quite right Ian, Mr Cabbage (aka Goldfinger) is worth more to us alive! 
https://www.youtube.com/watch?v=DoQwKe0lggw

Having done some rough tests - the main problems will be down to focus, power of beam and speed of motion.

The first jpg shows a shape with a setting of 100% laser and 1000mm s-1 a beam width of 1mm.

The second shows 50% laser 2000mm s-1 a beam width of 2mm.

The first jpg is a shape familiar to TGO and the latter should read Coal Hill Lane NW2(!)





Regards

Ralph

A few days later and the clamping table looks like it has gone ten rounds with a dragon!!! The main problem I think is down to me. The protective green glasses they supply render the laser beam invisible. This means that you have a choice of either hoping you have the right start position or being dazzled.

The next step will be to find some means of downloading the Gcode file from some source other than my computer. Ideally something that can read a flash or thumb drive(?)

Regards

Ralph

There are probably several ways to do this Ralph - but my 'go-to' currently for small stand-alone programmable 'things' is the Micromite system. I use a 64 pin PIC32 version (called Explore 64 - a MM+) as a kind of electronic pen-knife. It supports a wide range of I/O, including a USB console connection and has an SD card on board. So I can write simple utilities/programmes and store them on board - things like the Servo Tester I did for my early BDLC experiments.

I normally just use the USB console connection but there is built in LCD touch screen support that would make any stand-alone project very user friendly. The HLL is a modern, structured BASIC that is quick and interactive (e.g. no compile/test/recompile/load/test cycle) - you can edit directly 'on-chip' using the built in editor - or via MMEdit (a PC based Editor). You can buy an Explore 64 - RTR for £30 - see here:

https://micromite.org/shop/micromites/micromite-modules/micromite-explore-64/

With the addittion of a touch LCD screen - you would have a stand-alone system - or (to keep costs down) a simpler LCD with keypad would also work.

I also use/build simple 28pin PIC32 MMs (which cost about £3.60) - a fully functonal system with the addition of one external capacitor - that can work off two AA batteries. Add an IR detector and H-bridge - and you have a programmable IR controlled sytem for small DC motors - for custom solutions.....

MM Basic runs on a wide range of PIC32 and STM systems, as well as RPi (I have it running on RPi 3B - it's very fast indeed) but it works on the RPi Zero too. I also have MM Basic on my laptop (but it only supports serial comms - still very useful via USB).

So that's my starter for 10!  (Of course - you could also buy a 'Blue Pill' (about £2.60) and load Mecrisp Forth on it if that suited you better - you could then write a custom 'Laser' GCode language....

Let me know if you want any assistance with any of these suggestions - happy to help.

Regards,

IanT

Something to think about and I may take you up on that!

This is shot of it in operation, the laser is only running at 10%...





Regards

Ralph

Hi Ralph,

My E64 is shown above plugged into a breadboard but not actually connected to anything. As you can see it is a bit smaller than the two AA batteries.

The (rather messy) proto-PCB has a 28 pin Micromite plugged in (there are female pinouts on either side of it simply for convenience) - and this is running off the batteries. The MM is connected here to a Vishay IR detector (also plugged into the breadboard) by the three leads. I've some cheap (£1.82) Chinese TV controllers that this arrangement can 'see' - and each key pressed gives a unique code (which currently is just displayed on the laptop connected here via a serial/USB adaptor.

I've not added an H-bridge to this arrangement yet (been busy with other stuff recently) but as you can see - the whole thing can be made much smaller (and tidier) - a suitable MM (for I2C) 50mm x 43mm PCB can be purchased for £3.00 - which is one solution but a custom MM/H-bridge PCB would be better for DC motor use in the longer term...

I've PM'd you the E64 detail...

Regards,

IanT

I've been trying to get a google translate on this topic but it's still coming out in gobbledegook 😂

Ok - Fair enough.

Ralph is thinking about a £30 stand-alone device that can store and load very large amounts of G-code (up to 32Gb) into the control electronics (Arduino + GRBL) of his new Laser cutter - without having to tie up his very expensive quad-core PC.

For about £6 you can build an Infrared remote-control that can be simply programmed to control things  - Servos (points/signals), Motors (locos), LEDs (locos/signals) - just about anything you can dream up in fact. It can also hook up to all sorts of other tech. One 'remote' can control multiple devices in fact.

Both solutions are based on the same technology and are very affordable, especially when compared to most proprietary options.

Does that sound a bit simpler   :-)

IanT