Cnc Help/set Up
- Thread starter SweetJesus
- Start date
SweetJesus
In Memoriam
If you want a 4X4 gantry, I have the contact info if you want it. He also sells servo motor and controller for an additional 1500. So for about 3grand you can get a 4'X4' plus shipping the 350# crate. If your truly interested let me know, it will take him a month to build it for you!
Zephrant
Premium Member
Great info all- Those servos looked pretty steep though.
Here is the quote I just got for controllers, Servo motors, and a heat sink/case for all of them from a place near Seattle:
G320.G340 case $100
DB25 with screw terminals $30
Connector kit $30
4 amodule heatsink $25
4 G320 servo amps X$159=$636
4 600 oz in peak servo motors with 500 CPR encoders $169=676
Figure $38 s/h in the USA
Grand total: $1497
Camtronics
Not a bad price. You can also get the Gecko drivers direct from Gecko. The servos look like a good deal. The case/heatsink you could obviously build yourself too.
I've heard that the single flute bits are the best for acrylic, but have not tried them.
I almost picked up a bunch of T-slot extrusions last week-Over $350 of aluminum was going for $40 or so.. I was out-bid at the last second though, it ended up going for $79. Guess I should have bid higher, but I was concerned about getting it shipped.
T-Slots on Ebay
Zeph
Here is the quote I just got for controllers, Servo motors, and a heat sink/case for all of them from a place near Seattle:
G320.G340 case $100
DB25 with screw terminals $30
Connector kit $30
4 amodule heatsink $25
4 G320 servo amps X$159=$636
4 600 oz in peak servo motors with 500 CPR encoders $169=676
Figure $38 s/h in the USA
Grand total: $1497
Camtronics
Not a bad price. You can also get the Gecko drivers direct from Gecko. The servos look like a good deal. The case/heatsink you could obviously build yourself too.
I've heard that the single flute bits are the best for acrylic, but have not tried them.
I almost picked up a bunch of T-slot extrusions last week-Over $350 of aluminum was going for $40 or so.. I was out-bid at the last second though, it ended up going for $79. Guess I should have bid higher, but I was concerned about getting it shipped.
T-Slots on Ebay
Zeph
Zephrant
Premium Member
Hey- I've spent my spare time this week planning my system. I'm torn between a 5'x10' system and a 6'x12' system. It would not cost much more to build the larger size, but I can't think of a good reason I need it, other than "bigger is better".
I plan to use the Gecko 340's and the above servos. The nice thing about a servo is that it "knows" where it is supposed to be, and will drive full torque to get there if needed. A stepper will always use the same power to move one step, even if it only needs a fraction of that power to make the move. That makes the servos smoother and faster. The big thing is that a stepper can miss a step occasionally, which can ruin a part if it misses very many. The way to avoid it is to run the steppers slow enough that they don't miss steps. Perfectly acceptable, but the price of the servos is not much more and you never have to worry about it.
I'm not positive on the torque either. It does depend on your mechanical advantage too of course. I am going with a rack/pinion drive setup (similar to a shop-bot, but more rigid I hope). I will be using the 600 oz/in servos with two servos slaved on the X axis. The gantry will have 1200 on/in moving it around that way. But I'll also have a 2:1 belt driven reduction on each motor, so it will be 2400 oz/in effective. I can chance to a 3:1 ratio if that is insufficient. That would give up some top-end speed, but that should not be an issue.
The Shop-bot uses 350 on/in steppers on a 3.5:1 gear-box to drive a rack/pinion setup with two on the X axis too. That's an effective 2450 oz/in.
My setup will be similar to www.data-cut.com but bigger, and with dual X axis servos. I'll throw up some drawings when I get them done.
I'll PM you my phone number, give me a call in you want to chat.
Zeph
I plan to use the Gecko 340's and the above servos. The nice thing about a servo is that it "knows" where it is supposed to be, and will drive full torque to get there if needed. A stepper will always use the same power to move one step, even if it only needs a fraction of that power to make the move. That makes the servos smoother and faster. The big thing is that a stepper can miss a step occasionally, which can ruin a part if it misses very many. The way to avoid it is to run the steppers slow enough that they don't miss steps. Perfectly acceptable, but the price of the servos is not much more and you never have to worry about it.
I'm not positive on the torque either. It does depend on your mechanical advantage too of course. I am going with a rack/pinion drive setup (similar to a shop-bot, but more rigid I hope). I will be using the 600 oz/in servos with two servos slaved on the X axis. The gantry will have 1200 on/in moving it around that way. But I'll also have a 2:1 belt driven reduction on each motor, so it will be 2400 oz/in effective. I can chance to a 3:1 ratio if that is insufficient. That would give up some top-end speed, but that should not be an issue.
The Shop-bot uses 350 on/in steppers on a 3.5:1 gear-box to drive a rack/pinion setup with two on the X axis too. That's an effective 2450 oz/in.
My setup will be similar to www.data-cut.com but bigger, and with dual X axis servos. I'll throw up some drawings when I get them done.
I'll PM you my phone number, give me a call in you want to chat.
Zeph
Zephrant
Premium Member
The only thing new is that I have decided that I can't afford it yet. 
We decided finish the yard, put in grass, etc... so the cash I had set aside to get started got converted in to dirt.
I still have hopes of getting it together this fall... I have lots of plans for it.
Zeph
We decided finish the yard, put in grass, etc... so the cash I had set aside to get started got converted in to dirt.
I still have hopes of getting it together this fall... I have lots of plans for it.
Zeph
p4ck37p1mp
Premium Member
tagging along.
seems like the table is the hard part, by that I mean it is not cut and dry, like the motors and so forth are. Keep us informed when you continue on with your build of it
P.S. What size did you build your table ? Any pictures to share ? Any design specs or other info that would help others ?
Thanks in advance
P.S. What size did you build your table ? Any pictures to share ? Any design specs or other info that would help others ?
Thanks in advance
Zephrant
Premium Member
The table is 12'x6', so it will have a usable cutting area of 10'x5'+.
The tough part is that I'm trying to do it on the cheap- Instead of spending hundreds on mounting blocks for the shafts, I bought aluminum stock. So I'm at the point where I have to run that stock though the saw/mill to make the mounting blocks for the shaft (36'). To do that I need some help, and to be willing to throw aluminum shavings all over the shop.
The plans are my own- I can't post anything without knowing that it will work. There are a lot of pictures on the web though, and it is easy to draw up your own from them.
Zeph
The tough part is that I'm trying to do it on the cheap- Instead of spending hundreds on mounting blocks for the shafts, I bought aluminum stock. So I'm at the point where I have to run that stock though the saw/mill to make the mounting blocks for the shaft (36'). To do that I need some help, and to be willing to throw aluminum shavings all over the shop.
The plans are my own- I can't post anything without knowing that it will work.
There are a lot of pictures on the web though, and it is easy to draw up your own from them.Zeph
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