bteddy
May 12, 2022, 12:05am
18
Topics in forum that support my statements. one
Whats inside the gearbox/motor?
So following in the footsteps of our patron saints AvE & Dave Jones, I took apart my gear box to see what secrets it held inside. Here is what I have found…
[image] [image]
The gearbox (from my counting) as a 23:1 ratio from the motor output to output shaft. Both ends of the output shaft ride on a shielded bearing. Most of the gears are powdered metal with the exception of the worm shaft(motor output, single toothed, brass?) and the worm wheel (plastic). Each gear is held in place with steel …
Explanation of the math for moving the sled?
This is accomplished by the equations that @Joshua was asking about, where the straight chain length is calculated from the motor distance and sprocket radius. I found it was cleaner to accomplish it this way than to try to translate the motor position into a constantly moving point on the sprockets.
The chain angle is calculated based on the exit point from the sprocket, which is why the chain angle equations are different for the chain on top versus the chain on bottom configurations.
Frame Geometry Question
Will do.
I have scales to put in-line with my chains - I will try to connect them tomorrow,
I think I can do this without the motors running (I’m still waiting for a H-bridge board to arrive).
As a starting point to calculating the budget for the weakest lateral forces in the bottom corners, I think that the following sketch is correct. It calculates the largest lateral force (Gravity) before accounting for friction, router torque inertia, bit pull/bite, momentum, etc…
Does anyone see any …
Upgrading XY motors to double bearings and all metal gears
How much RPM are we currently getting? Will check that at the workshop tomorrow and provide the answer. From what I remember is that we are limited hard-coded by the firmware to F1000 and default in GC is F800. Wow that relates to RPM and how fast we could actually go is from my perspective somethig that people like (alphabetically) @bar @blurfl @dlang @MeticulousMaynard @Orob @zaneclaes and sorry for those i missed would be able to answer. The true ratio, the true Amps is something to be check…
Willing to open broken motor? Help needed
I consider this as fake news because I heard it several times and today took a witness to confirm where it’s coming from.
Edit: I had the witness press the ‘pull tight’ the second time so I would be on the ladder to make sure the sound is from the left motor.
Edit2: What would you like? The gopro is in the workshop and ready to record if a video would help.
Edit3: I am sure there is a beeping device in my left motor and I asked for help to find it.
Trying to convince the community that this…
X/Y motor specs vague
On my side this was solved with a 10A power supply and the TLE5206. With a 15kg sled at 8°.
With the TLE it was the first time to see a motor actually stall. Before it was just killing the original shield chips and/or the 5A power supply. I can’t calculate it, but i’m testing and observing for some time.
straight-line-curves-down-at-top-of-the-sheet-solved
Finding Center of Gravity for the Sled Ring
@Metalmaslow
How do you feel about editing your post? Personally, i feel it’s a wrong advice, but am open for discussion.
My theory (i’m trying to convince @dlang till date) is, that since triangular we have a moving CG on the sled as the ‘chain attachment points’ are moving, depending on how high the motors are and where we are on the sheet. 2 strings (non slipping), in the middle of the ring part the bearings are moving, would work, perhaps. A string at the top of the ring is not going to gi…
New Stock Frame Design
The frame design has remained largely the same while the other parts of the machine have steadily improved. The community has made a number of different frame designs each with their own strengths and weaknesses. It’s time that we collected the improvements the community has made and re-designed the stock frame.
The goals are:
Simple to construct
Uses low cost universally available materials
Provides increased rigidity from the original design
Let’s talk about features we like and designs el…
Gearbox Failure - Are We Exceeding Motor Design Limits?
I menioned in my post that I hadn’t taken that into account and that it was a missing variable. Sense you mentioned it, using our 14kg sled as an example, the amount of vertical load decreased due to the frame supporting the load is somewhere around 3-4kg. Per my post I also didn’t factor in the increased load to to the friction of the sled on the material being cut. That value can be calculated but is going to be dependent heavily on the construction of the individual sled. Which is why I didn…
Alternate Supply of Motors/Gears/Encoders
Hi folks,
Not being an engineer, the specifics of the worm gear motors is a mystery to me. I have been digging into the forums to try to identify the specifications necessary for the main motors to see if I can find a non-China based supplier (who will only sell in quantities way above my needs!) for my failures while the store is out of them. Hopefully something on a “usual” site, like Amazon!
Motor gears stripped
Hi dlang!
I don’t have this setup and I’m unfamiliar with the problems you guys are having.
Can you please elaborate on the problems you encounter when the sled is high on the board?
I know as high the sled gets, the more force the motors need to keep pulling it up, as closer the sled is from the same height of the sprockets harder it is for the motors, to the point that the motors will be pulling against each other.
But if you add weight to the sled AND compensate it on the counterweight s…
Another left motor gear failure, need a solution
I disagree with this assessment (although agree that the current calibration
step is wrong)
you do want to stretch the chains. We need to measure the difference between the
chains under tension and the theoretical chain length to know what the chain
slop is.
you also want to be able to see if the frame flexes under load or not.
The chain breaking strength is something line 900 pounds, and it’s normal
operational load rating is something like 200 pounds.
If the power supply and motor shie…
Triangular Linkage Evaluation Criteria and Measurements
If that were the case, that would explain a lot. I noticed that the Z-Axis wasn’t moving as much as it should have during the 27 square test. When retracting, it would slowly turn (like, very much slower than usual), or not at all. I had thought that maybe a wire had gotten disconnected, but it also would be entirely possible that the router was getting hung up on the Z-Axis motor. I looked through the video I took yesterday but the motor and leadscrew weren’t lit well enough for me to really s…
Fun with Numbers - Calculating Motor Load Force
This shouldn’t be a problem for a top beam frame. The only thing I’d really be worried about would be any play in the chain links, and any play in the linkage system. The latter shouldn’t be an issue, although if there is any slop in the system, the top of the machine is where we would notice them the most. I remember seeing posts that mentioned that there could be play in the chain links, which would obviously add up across a longer span of chain. Is this actually an issue or am I worrying ove…
Calibration pattern for triangular kinematics
I’ll do this and report back.
The ‘workarea’ sheet isn’t necessarily exactly centered between the motors, or exactly square to them. Errors in that part of construction would introduce error in the calibration. Better to use the motors to eliminate those construction vagaries by having the motors pay out fixed amounts of chain.
It might be hard to be accurate centering a router bit over a snapped location. What we really want are two known points on the vertical line centered between the mo…
What is distance of motor mount to worksurface?
Motor distance question
Thanks Bee, Im using .99 and .99. I got things working much better today using tape measure and manually entering measurements. I just have to fix up the top beam now to hang out over the work surface as per dlang.
What is correct chain pitch?
Thanks to @dlang and @JDogHerman who both took apart their motors (three times for David) so we could count the gear ratio and @blurfl for his expert assistance it looks like the gear ratio is actually 289.776234568:1 resulting in 8113.7345679 steps/revolution. (i was close empirically with 8114).
Changing the gear ratio in GC should to this value should solve the issue.
You can find the discussion and photos to perform you own teeth counting here:
25 more I got tired.