RC Tank Warfare community hobby forum

Well I have either got the beginnings of an Austin K2 ambulance....or a completed garden shed...

Pushed the printer to the limits on this. No support material used, so all vertical edges are wafer thin and printed without anything holding them vertical. Only one tiny top area went wonky, so I have cut it off and will infill with styrene.

Looking good.

Guess there's no need to buy anymore kits when you can just print your own.

@Woz - This is all getting obsessive compulsive, I wonder if there is clinical treatment available?

How long does it take to print something like that?

Due to the limitations on the size of the print bed, large models have to be split into sections. This is where the fun and games start during the design process. It's only by experience that you learn how to construct a model on the screen so that it can be broken down into component parts that will fit together once they are printed. If I had to give a ballpark figure, it's 80% design time, 20% printing time. It's also much easier to design and print an entire model on screen, rather than make parts to fit an existing one in my book.

With this model, the floor and sides of the rear were designed as one piece, a rectangular box with a smaller box removed from inside of it, leaving a hollow. The thickness of the walls depends on how wide the inside box is.

All of the design work is done using Openscad. Everything has to be constructed using spheres, cylinders, cubes/rectangles. The size and orientation of each of these is how a shape is built.

This was then cut into four sections using Netfabb.

Each section is then loaded into a program called Cura that slices each section into layers so that the printer knows what to print as it builds the layers up. This is called a GCode file, same as CNC machines use.

Each file is then loaded onto an SD Card that is inserted into the printer, the file is selected from an LCD screen, and then I can hit the print button.

On top of all of that there are settings in Cura that tell the printer whether to print supporting structures, the infill density, top and bottom layer thickness, print temperature, flow, print speed etc. Once a printer has been fine tuned its usually safe to save most of the settings and keep using them.

As for time on Katy?
2 roof sections took over 2 hours each.
4 rear sections over 2 hours each.
1 rear door panel with vent 1.5 hours.
2 side vents 20 minutes each.
1 rear cab panel with the spare wheel 4 hours.

I used to sit and watch the printer like a hawk, but now that it is running flawlessly I tend to go shopping, watch tv, visit friends or work on other models, then come back to it when its finished. Pretty easy way to model in that respect.

Nice work Rob,

Like that a lot.

John

5 hours later, and the cab is done...jeez. I can't glue it together as I need to primer and paint the inside, fit a steering wheel, seats etc.

Hi Wibbly, Amazing build thus far.

If possible could you please provide details of your 3D printer so that
I can start looking into prices and asking the good lady?

This is the one that I have, it took around 12 hours to assemble. It looks complicated but it's all very easy, the instructions are flawless, I never had any problems at all. The only thing I did that wasn't in the instructions was to use an M3 thread cutter before inserting the M3 allen bolts into the plastic, it made the whole thing rock solid.

With hindsight I would have asked the guy to supply it with the crimping and soldering done. The tiny connectors are a nightmare to do without a proper crimping tool, they took me another 5 hours. It mentions drilling etc in the Ebay ad, but this is just mounting the base of the printer onto the supplied MDF board, nothing technical at all.

Ebay
http://www.ebay.co.uk/itm/New-3D-Printe ... 35e8d8111c

Assembly
http://build3dparts.com/wp/?page_id=55

The key thing about this printer is that it has a self levelling bed. This makes a huge difference, and means that when I remove the glass to wash it off, I can stick it back in, and simply print again. It always self levels, so there is no messing about with configuring anything. The LCD screen has a built in SD Card holder, so you don't need to leave it hooked up to a pc while it is running, you can turn the pc off, and control the printer from the LCD, eg select print item, start print, abandon, pause, speed, temp and lots more. In reality I only use the speed adjustment nowadays, slow for the base layer and then ramp it up a bit when that is done.

I print using PLA, so no heated bed required, makes things very simple, PLA can be printed in your lounge, it has a very light and not unpleasant odour. ABS on a heated bed is apparently more intrusive, and of course, more expensive to run (it will be running for hours at a time).

All 3D printers do pretty much the same thing, they heat up a filament, and slowly extrude it through a nozzle, while the printer does a layer and then moves the nozzle up a layer to do the next one. Spending a fortune on one isn't going to get you better results, it is the trial and error setup that achieves that.

I hope that helps, if you have any questions I am more than happy to assist.

RobG

Printed the front end as one piece today, it took almost 8 hours even at a high % print speed.

The cab and front came out so much better than the rear that I am reprinting the rear box all over again but as one piece. This meant pulling off the roof and cab roof and rear panel which are ok, and also means that I will have to reprint the rear of the cab holding the spare wheel. The original was warped slightly, and I am using this model to try and get as high a quality as I can for the whole thing. It will also be very strong as there will be fewer parts, so if I can find any RC kit at a later date, it will be an easy conversion.

Lord knows how long all of this will take, Cura tells me over 20 hours, the cost of the filament for the new rear box is about £5.