Good Evening Everyone,
i have a laptop stand file that i been working on. Every time i do a cut, the templates are off on alignment when stacked. What i mean is if i’m doing 6 cut on a 24in*24in 1/2 MDF board then stack the templates to create a shape/pattern. Can anyone help me troubleshoot it or tell me what i’m doing wrong.
Here are some pictures to help get the idea :
Here is my file of the template also
This is right when i got my cuts done on the X carve
Here is when i try to stack them and it is off.
If the same shape cut several times are different from each other you may have one or more of the following issues going on:
- Excessive flex, the sideway cutting force push the bit off path with different amount
- Loosing steps
- End mill not truly perpendicular (trammed) relative to the cut surface
Thank you for reaching out to help me @HaldorLonningdal
I am new to CNC World. I hope you can help me understand using CNC better.
I could be wrong but i do not think my machine/board is flexing. My board thickness is .51 and i cut my depth at .48 to hold everything together. If it flex? what can i do to reduce the flex?
I have no idea what is loose step and don’t understand by the end mill not being truly perpendicular. Can you explain or give me a short summary ?
Any machine, even commercial ones, have some amount of flex inherent to them. Another factor is backlash.
If you push your tool by hand by a certain amount of force it will be pushed a little off path. If the rigidity on your X axis is different froom the Y axis then your machine will flex/give a different amount.
You can test this by say carving 2x2" pockets to 1/4" depth but increasing feed rate between pockets. You’ll eventually see that the pocket dimensions will start to change when you have reached the potensial of your particular machine. The harder you carve the more force is applied and the more it want to deflect in the opposite direction relative to cut.
Our machines are open loop, meaning the controller tell any motor to move a certain amount of steps. But there is no control / supervision of the said steps have been completed, the controller just assume they are done.
Pushing parameters too hard, unsecured pulleys etc can cause skipped steps (step commands that arent converted to movement)
Okay thank you for great explainination on the what could be the issue.
- I will try to do slower cut and see how it will go. Is it possible the smaller the bit the less flex if i have to sacrifice time ?
Like for example i change my 1/4 bit to a 1/8 bit and use the default setting on easel? To minimize loose steps, flex, and etc?
A tight, squared and trammed machine allow the tool to work better = increased MRR.
Less aggressive cutting = less force = less flex. (unless you go too slow which will cause the bit to rub vs cut. Bit will get warm and discolour if that is the case)
Keep the 1/4" bit, its strong. Better to tune in the feed rates.
See your other thread for issues regarding reduced cut time
Are you sure all your patterns are identical?
Have you calibrated your machine? If you’re cutting the same shape multiple times in a single job, but they aren’t all oriented the same, your machine needs to be calibrated for them to actually be cut with identical dimensions.
I have double check my templates and all the shapes. They are identical. My guess is maybe my x-carve is not calibrated accurate enough. @MarkA.Bachman
My x-carve was calibrated few months ago. Is it possible it could be off or i didn’t calibrated my machine accurate enough? @cg49me
Hey everyone! i found out the issue! the v wheels on the z axis that hold the router was loose. It caused lot of wiggle movement. I have tighten it up and it cutting accurate !
I’m so happy. I appreciate all the information again guys.
Hope you guys have a good weekend