Club member Colin takes us through his first attempts at 3D printing.
The idea of 3D printing has always interested me. Being able to design and make your own models easily and quickly appeals from the point of view of having total control over the modelling and wargaming experience. Its therefore been interesting to watch the 3D printing technology evolve and see how early adopters have used the technology in the wargaming space.
As a casual observer and follower of the 3D printing scene it can seem a bit of a daunting area. There are lots of helpful youtube videos and other content on the internet to inform. But you do come away with the impression that it is still a complicated area to get into with choice of printer, associated software to drive the printer, and then setting everything up so that it just works seems non-trivial.
However this Christmas I thought lets give it a go and get hands on to see what its about. The first decision point is the type of printing technology you want to work with and there are two methods to consider here – Firstly there is filament printing which involves a roll of plastic which is then fed into a print head where it melts and is deposited in layers to build the model.
The other option is resin printing where liquid resin is deposited in layers and cured into a solid layer by UV light.
Filament printing is not as precise as resin printing, but tends to offer scope for bigger models, is faster and generally a more simpler experience. Resin printing is more suited for detailed models such as miniature figures but requires dealing with liquid resin which produces odours, has to be stored correctly to avoid exposure to UV light and then when the model is completed, it has to be cured and washed – a more messy experience
Initially I was thinking resin printing was the way to go but then decided filament seemed a lot more straight forward as I dont have access to a dedicated workshop area and just wanted to get up and running with as simple a process possible.
The printer costs between the two technologies don’t seem to differ much and this then drives the next decisions – how much to spend and which printer to buy.
There seems to be three cost categories of printers – Professional £1,000+ , top end hobby £600+, and entry level hobby between £150 and £350 with many supplied as self assembly in this category.
One of the best known brands in the entry level category is Creality with their Ender product range. The Ender 3 is promoted as that offering the best and biggest community support. I’d come across it before and seen some of the youtube content explaining how it works and comparing the various revisions. It so happened when I was looking to buy that Creality had just announced the Ender 3 V2 which came with some significant enhancements to the previous version such as a heated print bed and so I decided to go with this. The printer is made in China and stocked by Amazon for about £250.
So come Christmas day the printer was revealed from Santa’s sack and the challenge with constructing it began. Its a kit model and suggests a couple of hours are required for assembly. As i say above there are lots of supporting community videos with guidance here. My advice in retrospect to anyone attempting the construction would be to spend some time in advance and watch some of these videos. I just ploughed on, with the instruction manual which can be a challenge and really needs a decent translation into English but on the whole it is fairly navigable as far as the actual construction is concerned. Every now and then I got stuck and had to quickly google for a helpful video just to make sure I was on the right lines.
Eventually I had the machine constructed and powered up and I now attempted to do an initial test print. Thats where the fun started. Before printing the machine must be calibrated in terms of the print bed position and the dispensing end of the filament. The manual explains how to do this using a piece of paper as a feeler gauge to setup ready for printing. However there seems to be a fundamental instruction missing from the manual regarding calibrating what is termed the z-stop. This is a switch which tells the printer where the bottom of the z vertical access is in relation to the print bed. If this is incorrectly set its impossible to go through the software driven instructions from the LCD panel on the printer. This was probably the biggest obstacle to overcome and eventually the right youtube video was found which clarified how to manually adjust this ready for calibrating the print bed.
So now with it ready to print you need something to print. This opens up the other side to the activity which is using software to design and build the 3D models for printing. A micro SD card is the storage mechanism used by the printer to access the models, and an LCD panel with a navigation button is used to initialise the printer and select from the SD card the model you want to print.
The printer comes with an SD card loaded with some sample models and a USB adapter for plugging the SD card into a computer and downloading models created there. And its here that the whole area comes alive. There are thousands of freely available models to download for free and print with many wargaming examples. www.thingiverse.com is the leading site here and is a great starting point for finding ready to go models.
Taking a step back if you want to design your own models the process starts with 3D computer aided design software. There are free applications here which are very professional and full function such as Blender. And there are easy to start with services such as tinkercad.com which runs in the browser and allows you to design using very simple building blocks with next to no learning curve required. The output from the 3D CAD application is an STL file.
In order to send this to the printer it has to be sliced, and for this another computer application is required. The Ender printer supplies an application called Cura, but there are others available for free. The slicing application asks what printer you are using and adjusts settings accordingly, you import the STL file which has been created by the design software (or downloaded from thingiverse for example), and then the slicer splits the model into slices on the x-y plane which the printer can understand and print. The output from the slicer is a GCODE file which you then transfer to the printer via the SD card.
Within the slicer app you can adjust the model in terms of scaling it up or down or cut and paste to create multiple models.
The first models I attempted to print were some wargaming items from thingiverse and this brought me back again to some of the issue with the printer setup. Bed adhesion seems to be the main topic of conversation on the community sites. If the print bed is not precisely level then the model will not adhere to the print bed and will slip at some point in the build process and ruin the print. With the early printers a common solution is to put down a layer of masking tap on the bed and start the print on that. Or use glue on the print bed or even hairspray. The heated bed on my model of printer aimed to solve this problem but because the bed levelling is a manual process there is scope for not getting this quite right. I struggled with a couple of initial prints here, and then after the usual search for an explanation on the internet just resorted to putting down a layer of spray glue which solved the problem and successfully produced my first prints. I subsequently resorted to a Pritt stick which works well and eventually graduated to no glue prints.
The other thing to mention with the output from the slicer app is supports. Because the printer works with layers from the bed upwards it needs a degree of continuity from one layer to the next and can only cope with overhangs of around 45% to the vertical. For models which fall outside this constraint the slicer app introduces supports as part of the build which can be removed after printing. The type of support, density etc is a complicated subject in its own right but for those aiming to build complex models is a key necessary understanding and often comes down to trial and error. With block type structures such as tanks you can get away with simple supports and/or re-orientating the way the model prints – so gun barrels are best printed vertically for instance.
Its worth mentioning at this point the economics of the subject. Along with the printer I got a 1kg reel of PLA plastic. This cost around £20. So 2p per gram of print material. A lot of the models I mention below are produced with 1 or 2 grams of material. So the potential for building models at a few pennies each is clear.