Hi
I've been collecting parts now for some time and getting close to begin the actual build, but i would like some thoughts and comment on my plans and Ideas.
What i want in the end is a cnc drill and mill capaple of drilling and milling pcb, milling stuff from wood to aluminium. Probly starting off with my dremel. I seen many here saying that it has much play so I might no be satisfied with that one, and it is freaking noisy!!! What about a BLDC Inrunner for model aircrafts?? Seen the in the KW range and they are good for at least 25K?
And as everybody elses this machine has a very tight budget and will be made with what i have lying arround. Budges estimate: 600$ give and take some
For the frame I'm going to us an old table with a steel frame, square 25mm x 25 mm tubing. Maybee if I'm able, I'm going to get a 1cm steel plate as base plate so i have a reference are from which i constuct the axes. Depends if i can get a hold of one cheap, dont think I can buy this on Ebay! I've read that it is good to have some weight to avoid resonace, at least to get the resonance frequency as low as possible.
The size of the table is 500mm x 600 mm. Because i live i a small condo it is going to be a moving gantry design to maximise the working area vs total size. I do not poses any advanced tools when it comes to the actual making of this machine, so my plan is to use the machine to improve it self when it is roughly finished.
The gantry is going to be made og aluminium, probably 4mm thick plate reinforced with solid 15 x15 mm square rods.
The slides and the screws is taken from a comercial cnc solder paste press.
My first misstake, why did i not just take the whole assembly!!!!!
A little luck after all, the slides are exacly as long as my frame!
The screws has a travel of about 1 cm pr rev.
My problem here is that the screws are 15 cm to long and made of hardend steel, how can I reetol them and fit them with new bearings?
I have decided to go for a DC servo solution using the UHU controller.
http://gsst.wikispaces.com/UHUget
The reason for this is that i have three DC servos that i think will fit my needs an if i like it should not be wery hard installing much moore powerful motors if needed:
Im probably going to use optical shaft encoders from US digital:
http://www.usdigital.com/products/s4/
Think these shuld do the trick! Have no clue about the CPR count i need yet .. . Probably in the area of 200 - 400 i guess . .. ?
X axis (The whole gantry)
DC servo from Bodine Electric
130V 1 A 2500RPM 1/8 HP
Probably driving the screw with a timingbelt solution with a shaft encoder on the screw, or the motor?????
Anyone got an idea of the ratio i would need here?? 5- 1 ?
The Y Axis
A DC servo from Japan Servo 127K1010
[URL="http://www.cnczone.com/forums/showthread.php?t=23730"][/URL]
(Thank you salahz for the info!)
Rated for 24VDC, 400ma, 2000RPM no load. LAB TEST BELOW:
RPM TORQUE (oz-in) Current
----- ----------------- ---------
2160 no load 400 ma
1740 30 2.2 Amps
1290 60 4.2 Amps
700 90 6.3 Amps
stall 100 7.6 Amps
The Z axis I've not yet decided but im thinking of another DC sevo from Japan Servo bu this one i hav very little info about.
There is a sticker on it that saysType: DS48BT25-2 EMF CONST: 6,4V/KPM iis this useful in any way?
I also have a bunch of small DC servo motors that only sasy RS-545PH with an optical encoder attached. Probably cant use the encoder since it is not incremental just the old tacko style.
The problem i see comming her is getting the motors attached to the pulleys since I've got axels in all shapes and sizes! An also the attachment of the encoders might be a problem since it is a very delicate instument!
I will post picture of my progress and of all the parts in this thread as the construction comes along.
I'm very new to this and I got lots of plans and ideas in my head, I might be way of on a lot of things so please coment!
I'm from the suthern parts of norway and would really like to come in contact with others of my kind.
I also hide behind this fact when it comes to my written english language, have me excused it is not my native language!!
best regards
Christian