Okay everyone I have been working on a new Zen for a long time now but I am really trying to get more serious about it.
I have all sorts of things that need improvement but here is what I have on my list.
Goals
-Try to make it so it fits in any current ZenXY table/build…at least the glass part. Trying to keep the same or larger “work area” within the same size constraints as before including the mechanism to glass gap.
-Low unique part count, unfortunately not the same parts as the previous Zen (expect steppers). I felt this was not a concern since the initial part count was really low.
-Fully constrained rails. The last one had chatter and did not lend well to you speed demons.
-Mechanically quieter, I am currently using small wheels (inexpensive).
-Same magnet, but hopefully room for more.
Differences (so far) that ya’ll might not like.
-Up to 10mm belt. Also means you have to use larger idlers. You can potentially use the same belts and pulleys though.
-2 sizes of rails. Currently I am using 3/4" for the long axis, and 1/2" EMT for the short axis. (I intend to make an international or two version as well).
-Shooting for no endstops but have not gotten that far. Trinamics are dirt cheap and allow for silent stepper driving (important) and they come with the ability to sense home. less wires and hardware. the cost of endstops and wires and wire management is probably the same as some trinamics. win win.
Questions.
1- Open source? Keep it civil, I am asking for any pitfalls you might see. I feel like this could be a fun test into the fully open world. Any ideas to help keep the project profitable as well?
2- Threading into printed parts? I am trying to decrease the part size and not using nuts on some low force screws seems like a waste. Also saves on part count/cost. So threading M5 screws directly into plastic and orienting them to also work with gravity seems cool right? A drop of loctite can actually help if any of you have loose screw holes after printing.
3- Board options. Sensor less homing, small cheap? Headless?
I think you would get more donations if you have a setup where people can choose what to pay, including zero, but with a suggested price for the files. Are you thinking of selling hardware and printed parts?
What control board are you thinking? Are there any 2 axis tmc boards with sensorless homing? I know there is a tmc grbl esp 32 board, but I don’t know if it supports sensorless homing.
I was wondering the same thing but I couldn’t find anything saying definitely one way or the other. Maybe still have mount points for limit switches if they are needed. But then, if you lean towards officially supporting Marlin based boards I get it.
Not sure if I can pull that off. I can look into it. Maybe set it up as a digital download from the shop, I can pull it off with a coupon code I think but not sure I can have a Zero cost item.
Maybe, well at least the parts, kits if needed. Have not actually thought that far through it. So far it is looking like wheels, M5 screw and nut, m3 for the steppers, belt. steppers and a board.
Not sure, headless would be awesome. I thought the esp did the sensor less…crud.
It is not complete yet. I will see what I can do, I intended to but the space is TIGHT so far.
RE: Goals
+1 for fully constrained rails and proper wheels.
RE: Differences
I think the difference in cost between 6 and 10mm parts is negligible, likewise if the difference between buying one stick of 3/4" EMT at $5 or one of each 1/2" and 3/4" for a total of $8, and there are gains in any category, again, I don’t think it would be enough to put anyone off on the build.
This is what i was thinking of. Sort of like the humble bundle. This even days it sometimes has problems though… Maybe the download link is in the shop, and there are a bunch of $1 items that are just a donation and people can add as many as they want to the cart? Not sure that will accomplish the same thing.
Why not use sheet metal screws instead of M5? It seems to me they would have a better bite into the plastic. There are also special purpose screws for plastic, but they might be harder to source. Does the ESP board have WiFi? I seem to remember sending gcode via wireless with it. That would be awesome…
Esp does have wifi. It works pretty well and it is sort of a separate app than the core grbl code. It can also read from an sd card. It seems like the perfect board, but I’m not certain it can do sensorless homing. I would like to spend some time trying to make a playlist functionality for the sd card, and a loop button.
They are most idler axles and not really doing any holding in the axial direction. Hope to print another prototype this evening, for the truck, still have some way to go but looking promising now.
Have you thought about Heat inserts? They are cheap (a few cents each), and weigh next to nothing. they can help a lot for 3d prints (was looking at them myself for another project.
Yeah they are a possibility but I do not think they are needed and they do take more than basic tools to use. If nuts are needed there is room but we’ll have to torture test it to see.
On my build (not zenxy but custom) I used ramps 1.4 (20$) and 2* bigtreetech2130 drivers (9$ each on banggood). The ramp board is not configured for sensorless homing through spi but the pinout of the driver allows to put extra jumper wires to achieve the full control of the drivers. I followed a guide (I can look for the link if you want) and it is not that difficult. I’m running marlin wich requires just to turn on sensorless homing, set corexy mode (in my case) and the table dimensions. The only tricky part may be to fine tune the sensitivity threshold for the homing (still not that difficult in my opinion) which may be different between builds. This drivers have also the silent mode but I’m struggling with the bearings noise so I cannot say how much they can be silent…
Okay so baby steps with this project I guess. Slow but there has been progress. I think the last major hurdle is the belt.
Will everyone hate me again if I use a couple zip ties or do I really need to cram more hardware in to make screw tensioner? The is very very little room to spare.
Zip ties don’t bother me. If it was something that needed constant adjustment, sure, a tensioner would be great. But since it’s pretty much once it’s set, it’s set, zip ties are fine.
This was brought up earlier in the thread so here is some information about sensor-less homing on Bart’s ESP32 project.
From above link…
StallGuard
Stallguard allows for sensorless stall detection. If a stall is detected it can send a signal to the controller. This controller treats it like a limit switch. If you want to use it, there are jumpers under the ESP32 to connect that signal to the ESP32.
Important Note: You cannot use use normal limit switches when the jumpers are installed. The signal from the drivers and the switches will conflict and damage the circuitry. Do not use a CNC I/O Module in socket #1 if X,Y,Z,and/or A are jumpered. Do not a CNC I/O Module in socket #2 if B and/or C are configured for stallguard.
Note: The StallGuard feature requires a lot of tuning for each machine design. It is an advanced subject that we can only offer limited personal support with. It is not for Newbies. See this page for information.
This.