[hub]

why does it rule out dremel? i thought that lower speeds would help, no bits braking, bending, no "overloading" the frame, less heating up... but the reduction is a great advice. i thought already about that, but i couldn't figure out how to calculate the ratios

Because feed speed is related to tool (spindle) RPM & diameter. For wood, slow speed & high rpm burns the wood & damages bits. For metal depending of type, lots of heat & maybe hardening & tool wear etc etc..
Low feed = low RPM

[lamesh99]

Because feed speed is related to tool (spindle) RPM & diameter. For wood, slow speed & high rpm burns the wood & damages bits. For metal depending of type, lots of heat & maybe hardening & tool wear etc etc..
Low feed = low RPM

seems i got it all wrong. i reckoned, the slower the spindle moves across the material, less pressure it creates, thus less side effects. like metal filing. the slower you push the file, the less it warms up. nevermind, thank you for getting me on the right track.

one more thing, what router can i use, that is not too heavy and expensive? it doesn have to be anything special, just something fit for a begginer machine

[austin.mn]

An important part about keeping your tooling in good shape is matching your feeds and speeds. If you run a dremel, or in the case of my first machine, a rotozip, you will cook your bits. Running 4ipm with a 25000 rpm bit turning is good way to shorten the life of your freshly bought routerbits to nothing.

If money is a concern on this project, you could just mount a hand drill to your Z axis and use it for your spindle Yes, I know that a drill chuck isn't proper for milling... but it would run in a more correct speed for the feeds he will be doing. Or you could spend a little bit and get a sherline spindle, which would be a lot more precise and easier to mount.

What was your plan for driving the axis' around? You could go belt and use the dremel as long as you kept your cuts light, very light.

[robe_uk]

Hi,
I built and use the PicStep drivers and I am quite happy with them, although they have max current of 3A, while good for your first machine they may limit your future motor upgrade plans. When I built mine back in about 2006 you could get free samples of the LMD18245 chip which made it a great cheap driver, but the last time I looked you could not get them as samples and ebay seems to be the lowest prices for the chip now.

Good luck whatever you decide

[lamesh99]

@austin
i intend to use threaded rods (google translator). essentially, a long screw without a "head". i think, since my steppers have the 1.8deg step, it could actually be quite accurate. if the frame allows, of course.

@robe
tell me more about picstep, please. i cant get much out of it just looking at the schematics. what do i use for input? parallel port? and is it one driver, one stepper or something else?

[robe_uk]

@robe
tell me more about picstep, please. i cant get much out of it just looking at the schematics. what do i use for input? parallel port? and is it one driver, one stepper or something else?

Yes the input to the picstep is from a computer parallel port and you will need a breakout board which makes hooking up easier. You will need one driver per stepper and note each driver requires two LMD18245. depending on where you source these from could determine the viability of building them compared to buying a ebay driver. Have a look in the PicStep forum for more information although not much activity there these days, seems less people build these days as cheaper ready made drivers for the diy'er are more readily available.
That said I think the picstep is a great driver and Alan the creator has done a great job.

Rob

edit: short video of my machine powered by picstep at 4000mm/min, recorded on my mobile so poor quaility

[doorknob]

My Dremel has variable speed, so you don't have to run it at 20,000 rpm.

BTW, I wonder what the proper SFM value is for cutting the styrofoam that the OP wants to work with...

[eSilviu]

my biggest concern is, will i be able to use my laptop for control. of course, the laptop has no parallel port, so i ordered a USB to parallel adapter. will it work? i have no idea.

no, there is no chance in using USB/parallel adapter.
But you could use (with far better results) a CNC USB controller. All of this controllers uses microcontrollers that must be programmed prior to use. You can do this (if you know how, or if there is somebody to help you) or you could buy-it preprogrammed. By the way, PicStep motor drivers uses a microcontroller too.

One free software+schematic+firmware can be found here: CNCDuDeZ Software I have use that for a good period of time, and for a beginner is enough (at least to see the advantages of USB over parallel port communication )
If you are willing to pay under 100 usd on a software, and build yourself a simple USB controller (schematic and firmware are available) I can send you an other link.

About steppers driver, there are so many IC designed exactly for this function, that it won't worth building one with logic ICs and transistors...
for example L6208 (use-it, never blow-up), A3977, A3979, DRV8811 (used all three of them, blowed a few because the IC didn't appreciated what I want it to do ), TB6560 and many more.
First you see if your steppers are unipolar or bipolar, then search for an IC that can drive-it. Schematic should be simple enough, even for a beginner.

[lamesh99]

yep, tested the USB adapter last night, of course it doesn't work.
will test it this morning on an old XP PC.
my steppers are unipolar, from what i've seen at minebea pages. plus, i have 6 wires coming out of them
the slight advantage of "my" drivers is that i don't need a breakout board. but, i do have one, since i got it from ebay. i wanted to see what a completed driver looks like,but didn't realize it was a breakout until it arrived
@esilviu:
is there a driver schematic at cncdudez, or just a program?

@doorknob
i need to learn my acronyms
SFM? OP?

[eSilviu]

@esilviu:
is there a driver schematic at cncdudez, or just a program?

I have attached two versions. I have used the one with SMDs.

[lamesh99]

I have attached two versions. I have used the one with SMDs.

what software do you use? eagle or something else?

[eSilviu]

what software do you use? eagle or something else?

Eagle. use the latest version to be sure that files are opened properly

[doorknob]

@doorknob
i need to learn my acronyms
SFM? OP?

SFM: Surface feet per minute - Wikipedia, the free encyclopedia

OP: Urban Dictionary: op

[lamesh99]

success! today i managed to get my first diy-driver up and running. the driver is the one i mentioned in my first couple of posts. it's made of two IC's, 4516 counter and a 4028 decoder, and four power mosfets, each capable of enduring 200V and 9amps. power for the ic's came from the 7812 stabilizer, for the motors from an ac/dc adapter, 12V/4amps. then, during the experimentation, i realized that it simply doesn't work. i fryed one 9amps mosfet (don't ask,i don't know), and the 12V were simply too much for the counter to distinguish the signals from the LPT. furthermore, the circuit was made on pertinax, and a had some lines that "fell off" the pertinax, so i had a "cold solder spot" (not sure how to call it in english, the solder detached from the copper line). then, 5.6V was introduced to the ic's, and some "cold solder spots" fixed, and it worked! the motor just buzzed and "shook", but that was due to the missing mosfet, so it didn't have all the leads connected.
next step, more testing, producing the pcb on vitroplast, some modifications neccessary. but, it finally works.

[doorknob]

i had a "cold solder spot" (not sure how to call it in english, the solder detached from the copper line).

"cold solder joint"

Congratulations on your progress...

[lamesh99]

thanks, knob. unfortunately, i didn't get any work done, over the weekend (girlfriend). but tomorrow, it starts all over again, and maybe i'll have myself a build thread, after all.
thanks for all the help and input, everyone! :cheers:

[lamesh99]

ok, the friday test was a failure. when i got to work this morning, i re-tested the driver and nothing, zero. no movement at all. fried another IRF 630, replaced the IC's, added "pro" IC bases, and nothing. i even thought it might be the CMOS-TTL voltage "clash", but no, both IC's are CMOS. i got back to the original schematics, and after some brainstorming realized that one of the 4028's inputs (D, or A3) was missing his ground (at the failed test on friday, i accidentally shorted them without knowing, and it worked). a piece-of-wire later, everything works. finally, i got to properly test the driver, and the motor. i found out that at 1700 steps/mm, it loses sync, and stalls. after i finish the drivers for other axis', i'll test everything some more, to see exactly how it behaves, and if it needs any major modifications.

i plan on completing the schematics later today, so i'll post it here, in case someone is interested in a low-cost, simple-to-build beginner driver. the driver costs me around 10-12$ per axis. it may be more expensive than the chinese ones at ebay, but for me it was a great way to learn a bit more. i also like it because you can "follow" the signal, as it exits the LPT port, enters the splitter board, and onto the driver board across the 4516 counter into the 4028 decoder, which then signals the mosfets when to "allow passage" to the electrons of the ground connection, thus controling the motor movement. essentially, that's how the driver works.

i hope i didn't bore you to death with my posts

[lamesh99]

hi, it's me again
i came across some cheap steppers, and i would like some input.
Motors are:

2 x VEXTA PH 2610-01, 2 phase, 1.8deg step, rated 1.88A at 6v, and

1 x SANYO DENKI STEP SYN type 103-715-1, 1.8deg step, rated 1.8A at 4.7v.

these motors would set me back about 50$, and i wonder if i should buy them. i have found similar motors at ebay for 78$ for SANYO, and 300$ (??) for VEXTA.

got some pics, too:

[acondit]

That seems real high considering that you can buy new steppers from Keling for $49 apiece.

NEMA 23 Stepper Motor: KL23H2100-35-4B (1/4” Dual shaft with a flat) 381 oz-in
Specification Price: $49 (Inductance 2.8 mH)
Can be used for G540, G251, G250 or any other driver

Alan

[zeed]

yes,49 a piece + shipping 30usd + import customs somewere around 30% witch makes it around 105usd a piece....

Making a machine is much cheaper for you then for us not living in the USA.
I just ordered 3pcs 570oz motors from keling and will be paying around 330usd for a 195usd motors....