Another status update post from this end – today we’ll discuss the issues we faced in the original printer, and what we’re doing to address them:
Mechanical frame improvements
Machined drive pulleys
The first version had printed drive pulleys. And while those worked alright, there was the inevitable eccentricity due to deformation of plastic when the pulley was tightened. So the new printer is going to have all aluminium drive pulleys. Indeed, we’re extending this concept to remove all printed parts from rotating axes. This should virtually remove the jiggles, and give a lot of mechanical stability when the machine runs.
Finer drive belts
We used XL drive belts in the first version. (XL is the one on the top in the picture above) This has 5.04mm pitch. While this is alright – indeed the prusa mendel uses XL as its standard drive belt, this meant that we had to use larger drive pulleys to mesh sufficient number of teeth. This meant more torque requirement from the motors, which meant more current requirement, which is bad!
So, we went for the very nice 3M belts (lower one in the picture above), which are designed specifically for maximal torque transfer. The good things about this belt are the smaller pitch (3mm) and symmetric tooth profile (i.e. the belt fully meshes with itself), the contact surface of this belt with the pulley is almost 100%. And most of all, it is metric 🙂 so It agrees with our religious views 😉
Ventilation and COOLING
The lower cabinet in the earlier design didn’t have any ventilation at all, so the steppers and the driver card had a tough time keeping their cool.
The new version has (nice looking!) ventilation ducts and site for mounting a 40mm fan on the chassis:
Other mech improvements
The chassis now sports an indicator panel, which shows the status of power, both heaters, and X, Y, Z motors:
We won’t divulge what’s gone in here till the website is up! For a teaser, its something which will make the reality 3D useful beyond 3D printing 🙂
Build platform improvements
The build platform is literally revamped. The earlier version’s build platform was very heavy, and had an aluminium heated bed, and we faced a real tough time trying to level it! Then, earlier version used asbestos sheet, which, they say, is hazardous, and handling precautions are needed.
With the new version, we hope to have addressed all these pains. Now it uses Bakelite sheet platform (which is quite planar, and can stand the 110 degrees from the heated bed), with a heated bed PCB on top:
Due to all the heating involved, we couldn’t use the Acrylic build platform (the bright orange plate you see on the first version)… so we went for another PCB for the build platform. If you want to go for rafted prints, this platform is what you want to use:
This build platform PCB is optional though – you can even go for raftless prints directly on the heated bed PCB (it will be mounted with heater coil on the underside; printing on it won’t damage the PCB) … we’ll leave that on Individual’s choice!
Also note the 220×220 scale on the build platform 🙂
Well, this section doesn’t have improvements from the first version per se, but there are improvements from stock Gen6 PCB. It has the heated bed PCB in addition to the Gen6 board. (Gen6+ functionality – because that design is not open source yet!)
The website is coming up at its own regular pace, and we’re working on the content. Most importantly it will include the Wiki (build instructions) and the user manuals.
The initial sourcing channels are almost set up, and parts are being built as per schedule. Since this machine includes the whole spectrum of components from mechanical to SMD parts, its a time taking exercise (but enlightening nonetheless)!
Until next time!