Ever so slightly off topic on the Morgan blog… One of my fellow House4hackers will be leaving soon, and has a large collection of tools, gadgets, hacks, printing equipment (printing press stuff) etc. that he would like to land in good homes before the metal recyclers have a go at it. I am going to get some stuff there for sure, but there are a lot of good toys to be had…
I added my calibration phantom and spreadsheet to the Morgan git repository.
Print the STL, and enter the measurements in the spreadsheet. It is not perfect, but take the guesswork out of calibrating the steps per angle.
Remember to keep the calibration guide in mind when changins steps per mm. The offsets change when the steps do, and you will have to reprogram the theta 0 and theta-psi 90 angles again.
After a very peaceful day self doubt is kicking in and I am wondering if the software is now too strict. Are you being locked out of the forums? Let me know in the comments, or if that does not work, contact me via github
I had to resort to installing an helper application to limit the amount of random registrations coming in… If your registration gets blocked by mistake, and you would really like to contribute or share in the forums, please contact me via Github. (qharley)
I noticed that the z-bed mount brackets were not created properly… There should be a 8mm and 12mm version in the repository, and it seems that there was only the 12mm, not named as such…
So! If you are building the 8mm rod version, you would probably have to reprint the correct bracket in order to make everything fit together.
The OpenSCAD models are unchanged.
Get your updated Morgan STL files from Github.
I am working on a assembly guide, but when printing a part on the new printer I found a simple calibration issue. The part came out ever so slightly oval. That set me on a path that took up quite a lot of my time… Too much, but what is what happens when you are on leave, and you have the time to play a bit…
Anyway, the idea is as follows.
- Print out SCARA-Cal, a special phantom I made for Morgan that initially helped me tweak steps per angle.
- Measure the following lengths marked on the phantom, Theta, Psi, X, Y and enter into a spreadsheet
- Said spreadsheet calculates Theta and Psi steps per degree, and the X and Y scaling required to make perfectly round circles.
My calculations are still a little flawed, but I am trying out a print right now… If it works right this will be the easiest way to ensure a perfect first calibration. If it does, I will re-add SCARA-cal and a quick guide with the spreadsheet to Git
Morgan is designed to be easy to build, easy to use and affordable, with less Vitamins than most – for example:
- 4 x Stepper motors
- 9 x 608z bearings
- 4 x LM8uu
- less than 1m smooth rod
- 12 x M8 nuts etc.
Although the cost of some of these minor vitamins are negligible the idea is not to only to bring down cost, but to lower the overall complexity of the design.
The process of printing with Morgan is exactly the same as any other RepRap. The Firmware takes care of the inverse kinematics that translates X and Y to Theta and Psi
Here are some vitals of the currently released Morgan:
- Configured build volume: 200x200x250 – 10 litre The possible build volume with a half-moon shaped build surface can be up to 30 litre (longest possible printable component could be more than 500mm
- Build price is dependent on the amount of recycled materials used. In the prototype the wood was salvaged from old packing crates, the pipes were recycled from old office furniture, half of the 608 bearings were re-purposed etc. Some of the more expensive components are also optional, like the heated bed, LCD display, SD card reader
- Print quality is not overly dependent on the quality of materials used, excepting possibly the linear elements in the Z-axis
- Print quality is also not highly dependent on the quality of the assembly, as long as the calibration is done according to the instructions. The firmware takes care of the rest.
Morgan is a long way from hitting the $100 material cost because of the excessive cost of some of the exotic vitamins, like the hot-end and electronics. These should be a lot less expensive, and it will be the focus of my research to find the way to make the material cost drop below that target.
Of course kits will never retail at those levels. People need to be paid to do that, and their time is expensive, but makers should have a choice depending on how much they are willing to pay versus how much time they are willing to spend.
A heartfelt thank you to the generous people that donated to Morgan to date. Your contribution, be it time, or money will be worth it when the next disruptive technology is spawned from the 3D tools we are seeding into the world now.
I have added a more detailed BOM into the assembly instruction page. This should make it easier to source parts at least…