marble sawmill

More
21 Apr 2024 23:55 #298807 by vre
marble sawmill was created by vre
Hello.
I want to retrofit a marble sawmill it is a x-y-z-c (c axis is rotating table) gantry machine but it cuts with disc not endmill. Cuts only linear and parallel to X axis due to disc does not cut arc nor with X-Y interpolation if you want to cut perpendicular to X axis (parallel to Y axis) must rotate the table(C axis) 90 degrees. In the same machine i want to put a spindle for carving like a xyz gantry router.
What config-kinematics is needed for disc operation and how can combine it with spindle
that is simple xyz trivial kinenatics ? Must use a second separate config or switched kinematics function?
Thank you.
 

Please Log in or Create an account to join the conversation.

More
22 Apr 2024 07:50 #298819 by Aciera
Replied by Aciera on topic marble sawmill
How do you want the two modes (saw/mill) to differ? They are both trivial kinematics but maybe you are thinking of disabling the C axis for the mill head?
Do you want to prevent the operator to move the Y axis with the saw down?

Please Log in or Create an account to join the conversation.

More
22 Apr 2024 16:03 #298849 by vre
Replied by vre on topic marble sawmill
yes that i want to prevent y axis with saw down

Please Log in or Create an account to join the conversation.

More
22 Apr 2024 16:59 #298852 by Aciera
Replied by Aciera on topic marble sawmill
Unfortunately there isn't an easy way to prevent the operator from issuing commands to move the y axis when the z axis is down. The interpreter will accept commands to all axes defined in the ini file so you will need to handle that case in hal.
It should be relatively straight forward to prevent signals from reaching the motor driver whenever the z-axis is lowered below a certain height. However this will not prevent the internal position to change to the commanded value. If you do have positional feedback a following error will occur, if LinuxCNC is not aware of the physical position then nothing will prevent the program from continuing. If the z-axis is raised above the set value the y-axis driver is reconnected to the internal step generator but the y-axis will not match the internal position displayed in the DRO. The Y-axis would need to be rehomed unless you devise a more complex solution that will bring the internal position back to the value the y-axis was before it was disconnected.

Please Log in or Create an account to join the conversation.

More
22 Apr 2024 19:56 #298860 by tommylight
Replied by tommylight on topic marble sawmill
Never mind the crunching/screeching sound, that is me, thinking...

Please Log in or Create an account to join the conversation.

More
22 Apr 2024 20:42 #298864 by vre
Replied by vre on topic marble sawmill
Machine will have servomotors with encoder feedback fro position to linuxcnc.

Please Log in or Create an account to join the conversation.

More
23 Apr 2024 06:15 #298892 by Aciera
Replied by Aciera on topic marble sawmill
The other option you could explore is using 'motion.feed-hold' or 'motion.feed-inhibit' pins.
linuxcnc.org/docs/html/man/man9/motion.9.html
This could, theoretically, stop any machine movement while still allowing the operator to jog the z-axis above the save height and resume normal operations without triggering a following error.
Given the dire consequences of having a saw go sideways you would want to thoroughly test whether this actually stops machine motion quickly enough. From a safety perspective it seems much better to disconnect the stepgen from the motor drive when the z-axis position is below the safe height rather that stopping the machine once the sideways movement has already started.


Of course you will want to inhibit jogging for the y-axis in hal regardless of how you stop the machine as that should be fairly easy to do.

Please Log in or Create an account to join the conversation.

More
23 Apr 2024 19:56 #298935 by vre
Replied by vre on topic marble sawmill
Robot arms like kuka have a function that you can set an area (inside limit switches) where motion is prohibited for safety reasons for example for human interaction / loading-unloading etc.. Exists something similar to linuxcnc?

Please Log in or Create an account to join the conversation.

More
24 Apr 2024 06:09 - 24 Apr 2024 06:29 #298969 by Aciera
Replied by Aciera on topic marble sawmill
Not as such but Joint and Axis limits can be changed using hal pins available in the ini. section after the gui has started. Note that the motion controller will only become aware of the changed values after a queuebuster command (eg M66 E0 L0).

[edit]
This is useful to clip or extend axis limits using M commands but it can not be used if the limits have to be updated continuously. For example if you wanted to change limits depending on the position of an other axis you would need to execute a queuebuster command through a hal pin connected to an MDI_COMMAND  which can only be done if the controller can switch to MDI mode at the time the change occurs. So you would again need to implement a safeguard in hal which will stop machine movements to avoid a crash but may require complex hal manipulation to recover from in an operator friendly fashion.
Last edit: 24 Apr 2024 06:29 by Aciera.

Please Log in or Create an account to join the conversation.

More
24 Apr 2024 12:20 #298991 by tommylight
Replied by tommylight on topic marble sawmill
Thinking out loud here, tollchanges can be set to move joints/axis to a set position before making a change, can the same be done for Y axis when a move is requested to move Z axis up before moving?
Or using external offsets to move Z up before any Y move?
The following user(s) said Thank You: Aciera

Please Log in or Create an account to join the conversation.

Moderators: cncbasher
Time to create page: 0.296 seconds
Powered by Kunena Forum