Post by jamesterm on Mar 31, 2022 2:32:14 GMT
Hi all I wanted to share the adventure with the Mega V, and all the details that went into it. I hope that we can compare notes and that I may be able to help out on some of my findings. I have all the pictures here that tell the story:
These parts are to this year's robot called Daydreamer... just in time for world champs good luck team!
For those who don't know this is team 3481 BroncBotz.
dropbox_link
First off, I am using solidworks with HSM express add on, which is auto desk plugin for solidworks and has a same feel like the CAM in fusion 360. In one picture I show how I can remote into the CNC machine from my home, where the mega V is in my friends garage. I only do this for dry run tests, where I have the z zero'd extra high just to make sure the gcode is valid and does what is predicted (also makes sure it doesn't hit the jigs).
Remote Dry-runs from raspberry pi's:
We are trying an experimental way to remote into the CNC machine by use of 2 raspberry pi's. One pi has raspian OS so that it can run UGS and it is hooked up to the controller. The other pi is using a web cam with ubuntu and we use WebRTC to have a low latency audio and video feed by use of NewTek's NDI software (we use this because I develop it and so I can test the code while I am using it). We use 2 pi's to reduce the CPU usage for the UGS as I didn't want it bogged down with anything, and the PI's are so cheap that it was feasible.
Drilling Divots:
I've found that using the 1/8" ball works great for making divot holes for the drill press, where I use chip breaking partial retract with pecking depth 0.01" accumulating pecking depth 0.01" chip break distance 0.02" dwell before retract for 0.25 seconds. I go down 0.06" (almost 1/16) so this will hit it about 6 times, and every pass goes all the way back up. This all happens really fast with the router set to the slowest speed (which is really too fast, but I don't have a spindle so I make due).
Contour Cuts:
Even though the calculator had 43.6, I used 35 ipm, with a depth cut of 1.5. I found this setting from someone cutting aluminum online. I also do not have tabs so this means but what I did instead is to make the rough pass a total depth of 0.22" leaving a small thin layer of 0.03" for the smooth pass to mill. When nothing messes up as shown in the picture this actually works great and the pieces don't fly off. So my first part I had some issues, and what this is is that for whatever reason the rough pass simply cannot remove enough chips, and about the 4th or 5th pass it gets too bogged down and will gum up on the bit. So to mitigate this, I do about 2 or 3 passes and start over. Since there are about 15 passes, starting over gets time consuming so it can take about an hour or so for one part. I found UGS can set where to start running the gcode from, so this helps but I only used that to get to the next part as it was easy to find where that was. At some point I'd like to work out how to make this an easier process, and I'm not sure if this is an issue for 1/8" stock but I suspect not having tabs may explain why I've had better success on the m3. Really this is not about the machine, the Mega V does indeed have more torque, but its about having a better understanding of how the chips are being distributed and also keeping an eye on the bit to make sure it is not dull. I don't believe they have gotten dull, but I still inspect them in case they do or incase they have some metal gummed up in the flutes.
Contour Smooth pass:
The rough pass is 1/4" bit, where the smooth pass is the 1/8", and since it is smooth I can use the 43.6 with a depth of 0.02". I also change the router from 1.5 to 4x to stay in the sfm range of around 800. I've always had success with the smooth pass since it has little work to do. When it get's to that last 0.03" inch it mills very well, it does get scary when it breaks off the final pieces though. I've had the pieces fly off, but they don't go too far. I've tried to stop the operation the moment I see it start to jar loose. I would like to use tabs but HSM express will not support them, and they are set on this decision. I have found this solution to be fine with this tradeoff.
Well that's it for now, this has been a success 3 years in the planning every since I bought it back in the fall of 2019 through the early bird kick start... took a long time to make it to this point but here we are!
I may reply with a pic or two on screen at some point but for now just use the dropbox link to see the pictures. I hope it helps you!
Any recommendations for the contour cuts would be greatly appreciated... I will come back again once we work out the details about using the boot.
These parts are to this year's robot called Daydreamer... just in time for world champs good luck team!
For those who don't know this is team 3481 BroncBotz.
dropbox_link
First off, I am using solidworks with HSM express add on, which is auto desk plugin for solidworks and has a same feel like the CAM in fusion 360. In one picture I show how I can remote into the CNC machine from my home, where the mega V is in my friends garage. I only do this for dry run tests, where I have the z zero'd extra high just to make sure the gcode is valid and does what is predicted (also makes sure it doesn't hit the jigs).
Remote Dry-runs from raspberry pi's:
We are trying an experimental way to remote into the CNC machine by use of 2 raspberry pi's. One pi has raspian OS so that it can run UGS and it is hooked up to the controller. The other pi is using a web cam with ubuntu and we use WebRTC to have a low latency audio and video feed by use of NewTek's NDI software (we use this because I develop it and so I can test the code while I am using it). We use 2 pi's to reduce the CPU usage for the UGS as I didn't want it bogged down with anything, and the PI's are so cheap that it was feasible.
Drilling Divots:
I've found that using the 1/8" ball works great for making divot holes for the drill press, where I use chip breaking partial retract with pecking depth 0.01" accumulating pecking depth 0.01" chip break distance 0.02" dwell before retract for 0.25 seconds. I go down 0.06" (almost 1/16) so this will hit it about 6 times, and every pass goes all the way back up. This all happens really fast with the router set to the slowest speed (which is really too fast, but I don't have a spindle so I make due).
Contour Cuts:
Even though the calculator had 43.6, I used 35 ipm, with a depth cut of 1.5. I found this setting from someone cutting aluminum online. I also do not have tabs so this means but what I did instead is to make the rough pass a total depth of 0.22" leaving a small thin layer of 0.03" for the smooth pass to mill. When nothing messes up as shown in the picture this actually works great and the pieces don't fly off. So my first part I had some issues, and what this is is that for whatever reason the rough pass simply cannot remove enough chips, and about the 4th or 5th pass it gets too bogged down and will gum up on the bit. So to mitigate this, I do about 2 or 3 passes and start over. Since there are about 15 passes, starting over gets time consuming so it can take about an hour or so for one part. I found UGS can set where to start running the gcode from, so this helps but I only used that to get to the next part as it was easy to find where that was. At some point I'd like to work out how to make this an easier process, and I'm not sure if this is an issue for 1/8" stock but I suspect not having tabs may explain why I've had better success on the m3. Really this is not about the machine, the Mega V does indeed have more torque, but its about having a better understanding of how the chips are being distributed and also keeping an eye on the bit to make sure it is not dull. I don't believe they have gotten dull, but I still inspect them in case they do or incase they have some metal gummed up in the flutes.
Contour Smooth pass:
The rough pass is 1/4" bit, where the smooth pass is the 1/8", and since it is smooth I can use the 43.6 with a depth of 0.02". I also change the router from 1.5 to 4x to stay in the sfm range of around 800. I've always had success with the smooth pass since it has little work to do. When it get's to that last 0.03" inch it mills very well, it does get scary when it breaks off the final pieces though. I've had the pieces fly off, but they don't go too far. I've tried to stop the operation the moment I see it start to jar loose. I would like to use tabs but HSM express will not support them, and they are set on this decision. I have found this solution to be fine with this tradeoff.
Well that's it for now, this has been a success 3 years in the planning every since I bought it back in the fall of 2019 through the early bird kick start... took a long time to make it to this point but here we are!
I may reply with a pic or two on screen at some point but for now just use the dropbox link to see the pictures. I hope it helps you!
Any recommendations for the contour cuts would be greatly appreciated... I will come back again once we work out the details about using the boot.
