It has been a long time since I've had the opportunity to post updates on some of my current projects. I'll be posting a number of more detailed updates on my motor controller, 3d printer, and Formula Hybrid related work in the near future. For the moment though, it's time to continue the printer build log. This will probably be more of a picture dump than I normally like to do, but there is a lot to catch up on!
In the last update, the last of the vertical milling operations were completed, and the frame was coming together for the first time. The frame was completed with no major problems, and the laser cut side windows installed perfectly. Installation of the z-axis, as predicted, was problematic at first. A number of tests with the Nema 17 motor revealed that the oil infused bronze bushings were creating more friction than I had anticipated, even with the flexure mounts doing their job. I deconstructed the z-axis and extensively reamed the bushings to loosen the tolerances slightly. as well and went through a much more careful alignment process as I re-tightened the t-nuts. Finally, I manually re-milled the motor mount bracket to accept a Nema 23 type stepper with almost double the torque. The z-axis movements are now extremely smooth and precise.
The x/y gantry mounts arrived from Shapeway looking great. Amazingly, the snap fit mounts I designed into the holders worked perfectly with the linear bearing, requiring no sanding or modification. I really have to compliment the SLS Nylon 3d printing process, the detail is fantastic, and there appears to be far less internal stress between the layers than with FDM prints. It took three design iterations before I got the components to a point where I was happy with them, but I think they turned out well:
The x/y gantry installation was a breeze. As a design note I may have forgotten to mention last time, the machine is composed of two pair of parallel shafts representing the x and y axes. An additional two shafts going across the machine transmit mechanical power to the timing belt pulleys running the belt behind the plastic bearing holders. This is visible in the image below. The coupling for those transmission shafts to the motor is seen at the lower right hand side.
This motor coupling turned out very nicely, and seems like it will be fairly robust:
This bring things back to the present. With the mechanics looking good, the process of wiring all the components together has begun. I've decided to route everything to a box at the back for simplicity, and keep the power supply separate. I'm also taking my time to ensure that all routes are as clean as possible and the connections are solid. Initially, I purchased 4 conductor automation wire from McMaster, concerned about the frequency of flexing that the cable would need to endure. It turns out the gauge was too low to fit in the terminal blocks of the Azteeg X3 controller, so I went back and just purchased some cheap 22 gauge alarm system cable instead. Remarkably, it appears to be just as good as the more expensive stuff so far, and even comes with shielding and a strain relief cable. Blue mesh wrap and zip tie strain relief keeps the cables safe and looking good.
I decided to pass on using connectors for this project due to the price. Instead, all wire just goes through grommets into the electrical box. Hopefully I will have the change to finish the wiring and begin working with the firmware over the next few days. Last but not least, I finally got the led lighting installed:
That's all for now, check back soon for a lot more updates.
