1st Section

FDM Printing

What is FDM Printing ?

FDM printing is very simply a spool of plastic filament being feed into a heated nozzle and laid down in thin lines over multiple layers in all 3 axis of movement. The size of the nozzle and the printer settings define the quality of a print, and the overall printer software package determines ease of use. The software takes a STL file and slices the file to create a 3d model that can be printed. STL files are widely available on the net, either to purchase or for free and if you have the ability you can also create your own. This does require a 3d program such as CAD or Blender and a learning curve. I taught myself 3d modelling some 20 years ago and so can make very simple models, or amend existing files.

I purchased a Bambu A1 mini last July for about £170 including an extra nozzle and some filament. Since that time I have purchased roughly half a dozen spools of filament and a new 0.2mm nozzle (the smallest size available).

I have 1807 hours logged on the printer and using simple maths ( I like simple maths and you will see it a lot in this blog) that works out not far off 10p per hour amortised cost. 

My printer normally sits on a wooden block under my game table and churns out prints on demand. There are no toxic chemicals used in the process, but every now and then a little bit of molten plastic on the nozzle will overheat and smoke a little, but in truth the most invasive thing about the printer is it makes a little noise. Shut the door and that stops being a problem. This is a small printer with a print bed 18cm x 18cm and so a model that is larger than that needs to be cut into smaller parts. Even with buildings I have not yet found a model I needed to cut more than I would wish to get it to fit. 

STL files

I have over 500 vehicle STL files all downloaded from the net. Some are duplicates of the same vehicle type by different designers but this is a massive pool into which to dip. To date I have only purchased two vehicle files (one was actually for a Pak40 which was £3-4 only, but in the event I subsequently found a better file for free).  So all the others are legitimately available, for free, from generous model makers who share their work.

Marco Bergman is one such 3d model maker and I think this is his full catalogue, with all models made at 1:100 scale (15mm). These are good quality models and comparable with 15mm white metal or plastic kits.

This is the other vehicle STL file I purchased - the Hotchkiss Geschutzwagen 39H - as I have not been able to find anyone else offering this oddity. 

I will do a future post covering the process of printing this model in detail but on slicing the file  the software advises this will use 8.71g of filament. Filament comes in 1kg spools, and I paid £8.50 for this spool. Print time will be 3 hours 43 minutes, and the cost for the print will be 7p. 

Yep - just seven of those shiny British pennies. 

I can therefore afford a few failed prints while I seek the best set up for this particular print and still be way ahead of the game. A quick check on ebay for a single AFV plastic sprue shows I would be paying somewhere between £4-10 for an injection moulded kit if one was available.

I will happily argue that printing vehicles and AFVs at 15mm (1:100 scale) is the sweet spot for the FDM printing process, particularly when the model was made with printing at that size in mind. I have reduced the size of 28mm models and printed them, but the level of detail becomes harder for the printer to cope with. There is no doubt a resin printer will produce a better model than a FDM printer. However at this scale the FDM printer is more than capable of producing good quality prints suitable for the table and at 7p a pop you can't go wrong. No messy or toxic chemicals to have to deal with either.

Everything but the tarps are FDM printed, including the commander