[Beginner] Deriving ratios to show on the UI
06 Oct 2023 02:53 - 06 Oct 2023 03:37 #282413
by rthorntn
[Beginner] Deriving ratios to show on the UI was created by rthorntn
Hi,
Apologies if this doesn't make a lot of sense. Please think of it as thinking around a "semi-manual" lathe that doesn't have any dedicated motors on the carriage or cross-slide.
I should start by emphasizing that I'm not a programmer and that everytime (in the last 30 years) I've tried to program I've hit a brick wall and also I'm a perpetual beginner hobbyist on CNC and machining. Please be gentle.
So on a lathe lets say you have a spindle RPM encoder, a VFD driven spindle motor and a glass scale on the carriage.
The lathe has a geared head with 6 spindle speeds and manual change gears to change the carriage speed. Does LinuxCNC have a mechanism to calculate and display a readout of projected spindle speeds (6 gears and the VFD changing the actual motor speed) and leadscrew speed (change gear configuration) based on the spindle RPM and the carriage speed?
For the sake of simplicity lets say that you have some way of manually input the current gear setting manually. I think it would be a case of calculating and inputting the 6 speeds into a lookup table for spindle speed. For feed rate it would be a larger lookup table with all the possible change gear configurations. I think the math would be something like this:
Rpm ÷ hz = ratio
Ratio x hz = rpm
And:
Rpm ÷ feed rate (micron/sec) = ratio
Ratio x rpm = feed rate
Cheers
Richard
Apologies if this doesn't make a lot of sense. Please think of it as thinking around a "semi-manual" lathe that doesn't have any dedicated motors on the carriage or cross-slide.
I should start by emphasizing that I'm not a programmer and that everytime (in the last 30 years) I've tried to program I've hit a brick wall and also I'm a perpetual beginner hobbyist on CNC and machining. Please be gentle.
So on a lathe lets say you have a spindle RPM encoder, a VFD driven spindle motor and a glass scale on the carriage.
The lathe has a geared head with 6 spindle speeds and manual change gears to change the carriage speed. Does LinuxCNC have a mechanism to calculate and display a readout of projected spindle speeds (6 gears and the VFD changing the actual motor speed) and leadscrew speed (change gear configuration) based on the spindle RPM and the carriage speed?
For the sake of simplicity lets say that you have some way of manually input the current gear setting manually. I think it would be a case of calculating and inputting the 6 speeds into a lookup table for spindle speed. For feed rate it would be a larger lookup table with all the possible change gear configurations. I think the math would be something like this:
Rpm ÷ hz = ratio
Ratio x hz = rpm
And:
Rpm ÷ feed rate (micron/sec) = ratio
Ratio x rpm = feed rate
Cheers
Richard
Last edit: 06 Oct 2023 03:37 by rthorntn.
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06 Oct 2023 03:22 #282415
by rodw
Replied by rodw on topic [Beginner] Deriving ratios to show on the UI
Yes, you can do anything with linuxcnc
The attched quick and dirty component does what you want with a 2 pulley belt drive. I use this with a QTdragon_HD panel called belts.ui.
After we developed the panel, its now avalable as an example and documented in the qtdaragon docs.
And yes, I use a VFD with QT dragon.
I measurerd the maximum speed (RPM) with a cheap digital tacho in the fastest gear and then measured the speed of every combintion of belts'I then calculated the gear ratio which I put into a 2 dimensional array (for the 2 belt) and it scales the output from the VFD to the correct gear.
You can install the panel, and connect this and play with it
Assuming 2.9 on debian, install this like this
sudo apt install linuxcnc-uspace-dev
sudo halcompile --install scalebelts.comp
Modify to suit your gears.
The attched quick and dirty component does what you want with a 2 pulley belt drive. I use this with a QTdragon_HD panel called belts.ui.
After we developed the panel, its now avalable as an example and documented in the qtdaragon docs.
And yes, I use a VFD with QT dragon.
I measurerd the maximum speed (RPM) with a cheap digital tacho in the fastest gear and then measured the speed of every combintion of belts'I then calculated the gear ratio which I put into a 2 dimensional array (for the 2 belt) and it scales the output from the VFD to the correct gear.
You can install the panel, and connect this and play with it
Assuming 2.9 on debian, install this like this
sudo apt install linuxcnc-uspace-dev
sudo halcompile --install scalebelts.comp
Modify to suit your gears.
The following user(s) said Thank You: rthorntn
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06 Oct 2023 03:28 #282416
by rodw
Replied by rodw on topic [Beginner] Deriving ratios to show on the UI
Here is the seperate hal file that connects the UI to the component
LOad it in your ini file
LOad it in your ini file
The following user(s) said Thank You: rthorntn
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