I've been a bit obsessed lately to reduce the time a repeating project of mine takes to cut using my Probotix Meteor CNC. Thought I'd share a few of the strategies I'm exploring, with the hope that I might read a few others from the brilliant members here.
First of all this project is parts cut from a 30" x 20" sheet of 18mm Baltic Birch plywood. It includes through mortise pockets, holes for bolt shafts and countersinks for the flat head bolts to be used, pockets for cross dowels and slots for the bolts that will intersect them, and profile cuts for 6 parts that fill most of the sheet.
Strategies:
1. Use only one bit to cut the entire project. Changing and Z-zeroing bits and loading a new toolpath take time and are an opportunity for mistakes to be made (like forgetting the new file).
2. Reduce the mess made (less cleanup time) by using a 3/16" end mill rather than a 1/4" end mill.
3. Reduce the # of passes used where possible. While the default pass depth is normally 1/2 the bit diameter, I find I can set a 3/16" bit to 1/8" passes as the cross section through the wood is still 25% less to remove than for a 1/4" bit at that same depth. Then If the software wants to use 6 passes I reset it to do the toolpath in 5.
4. Tabs slow down a cut when the bit slows to hop over them. I'll use as few tabs as possible to keep the part in place during a job. Usually 3 but sometimes just two on any part perimeter. Then I'll set the tab thickness to 1/5 or less the board thickness so the toolpath only hops over tabs on the last pass.
5. Cut countersinks with the end mill. I found I can use a rotary array of short vectors and the fluting toolpath to make a decent countersink for the bolt holes. No bit change required here.
6. Reduce clearance (Z1) and plunge (Z2) and Z gap above material to .1" or less. My Z travel/plunge speed is the slowest setting for every bit I have. Reducing the time the bit rises up between passes or new vectors makes a huge reduction in total cut time.
7. Set a Home/Start position in the middle of all the cuts rather than leave it at the corner I've zeroed X and Y at.
8. Reduce as much as possible the distance the bit moves between new cuts. Merging the bolt hole pockets with the fluting chamfer cuts means the bit only travels to each bolt spot once. Strategic use of vector selection order for sequential cuts can greatly improve on the software's (Aspire) default logic for reducing overall travel time.
The first time I cut this job the CNC was busy for 27 minutes. I now have that time down to 12 minutes, and with no bit changes or post processing to be done to the parts off the CNC. Less mess to clean up before I can load another board, meaning I can usually have two done in the time it originally took me to cut one.
So what strategies have you used to reduce a project's cut time?
4D
First of all this project is parts cut from a 30" x 20" sheet of 18mm Baltic Birch plywood. It includes through mortise pockets, holes for bolt shafts and countersinks for the flat head bolts to be used, pockets for cross dowels and slots for the bolts that will intersect them, and profile cuts for 6 parts that fill most of the sheet.
Strategies:
1. Use only one bit to cut the entire project. Changing and Z-zeroing bits and loading a new toolpath take time and are an opportunity for mistakes to be made (like forgetting the new file).
2. Reduce the mess made (less cleanup time) by using a 3/16" end mill rather than a 1/4" end mill.
3. Reduce the # of passes used where possible. While the default pass depth is normally 1/2 the bit diameter, I find I can set a 3/16" bit to 1/8" passes as the cross section through the wood is still 25% less to remove than for a 1/4" bit at that same depth. Then If the software wants to use 6 passes I reset it to do the toolpath in 5.
4. Tabs slow down a cut when the bit slows to hop over them. I'll use as few tabs as possible to keep the part in place during a job. Usually 3 but sometimes just two on any part perimeter. Then I'll set the tab thickness to 1/5 or less the board thickness so the toolpath only hops over tabs on the last pass.
5. Cut countersinks with the end mill. I found I can use a rotary array of short vectors and the fluting toolpath to make a decent countersink for the bolt holes. No bit change required here.
6. Reduce clearance (Z1) and plunge (Z2) and Z gap above material to .1" or less. My Z travel/plunge speed is the slowest setting for every bit I have. Reducing the time the bit rises up between passes or new vectors makes a huge reduction in total cut time.
7. Set a Home/Start position in the middle of all the cuts rather than leave it at the corner I've zeroed X and Y at.
8. Reduce as much as possible the distance the bit moves between new cuts. Merging the bolt hole pockets with the fluting chamfer cuts means the bit only travels to each bolt spot once. Strategic use of vector selection order for sequential cuts can greatly improve on the software's (Aspire) default logic for reducing overall travel time.
The first time I cut this job the CNC was busy for 27 minutes. I now have that time down to 12 minutes, and with no bit changes or post processing to be done to the parts off the CNC. Less mess to clean up before I can load another board, meaning I can usually have two done in the time it originally took me to cut one.
So what strategies have you used to reduce a project's cut time?
4D
