I have had more then a few problems setting up for the new turbocnc. But what i am looking for is should my driver be half step or full. If anyone can tell me what setup they have that is working for them then i can basically go from there. As right now i am using a cwtech board design with ucn5804b chips. I have 45 in/oz steppers running 3/8 by 16" i think " allthead. My settings in turbocnc is 0.0001525 for the setting then max them to 1000mhz. I am running under freedos, on its own partition. It seems to operate okay but i'm wondering if things can work better. Basically i would like to know what other people have as a setup and how well it is working for them. Any info will be greatly appreciated. Thanx.

Hi Tinker,

If your machine moves one inch when you command once inch, then your 0.0001525 would be correct. If not hit "C" at the Step increment menu item, and you will be given a simple table to fill in and TCNC will work out the mathes. If you are currently commanding one inch and getting 1/2" then the driver is probably set to halfstep. Half stepping should reduce resonance problems a little.

The fact that the machine is slow and looses steps at faster speeds (I am assuming this is the underlying problem), is probably due to gutless 45ozin high inductance steppers run at low voltage. Remember that the althread is pretty low efficiency stuff, turning about half what little power power you are feeding it into heat (although it is being feed so little power that the althread can disappate that heat without getting noticeable warm).

Sorry to be blunt. What are you trying to move?

Regards,
Mark

I have my x and y axis setup this way. Neither one is very large of a setup. But they are all driven with the allthread, i can turn the allthread by hand and its not that hard to do. Both axis move very well with out the lead screw attached so there is no binding. But i was thinking of using a 24v power supply i have rather then the 12 volt i am using. Plus the driver board i have uses ballast resistors. I guess i will just have to fiddle with it. Thanx.

Doubling the voltage (combined with the correct resisters so you don't burn your motors should increase you speed. What is the voltage and amperage relationship of the motors?

TinkerDJ,

If you've got 3/8 16 allthread,( and that's the common lead for 3/8,) then for turbocnc set (1/16)/200 or 0.0003125 full step and halfstep would be 0.00015625.

If your board follows the schematic then if you have it jumpered (so pin 10 is to earth) that's half step. I'd suggest you use halfstep if possible as fullstep on 5804's can be a bit rough.

You've said your settings are 1000mhz? or do you mean the default 1000Hz setting for max speed? if so that's 1000 steps per second or 9.375 inches per minute, halfstep. You could try increasing that until you loose steps and back off a bit. It could go faster I suspect.

Andrew

I'm currently building my mill with the same board and some weak motors. I was wondering if I put 2 motors and lead-screws, can I get them close enough synchronized to work together?

The motors are like 3 bucks each, and are pretty stiff but I suspect they would not be strong enough and only run well up to 300hz until I lose steps at 12v on a small foam lathe. I suspect they are 24 volts... I will bump this at 24 volts but are there any other tricks to watch for on the board except the resistors?

Thanks

Para

Yeah i blew a chip on that ucn5804b board and decided to build some new ones. I'm currently working on building several of Phil's designs from the open source area. You can use two motors there are several guys that have that. The only problem is getting the correct polarity so that they operate together and not against each other. The only one i have seen lately was using a drive belt. I think that was Mr Beans mill.

When i built the board there are a few things to make sure, when you've completed etching th board go over it with a magnifing glass or jewellers eye piece which is what i use, or a scope if you have one to make sure none of the traces cross or are missing. Then the most important part would have to be when you solder the chips to the board make sure and use a heat sink on the legs when you heat and apply the solder, also make sure you have a good heat sink on each chip. This is one of the reasons why i blew up the board, on the one chip the heatsink had slipped nearly off and the chip thermalled. There is a few excellent posts on using the ucn5804b chips and a couple of diffrent designed boards in the forums probly be good to do a search. But if you haven't started the board yet i would recommend building some of the boards on Phils sight and at the very least build his Break Out Board. I do not in anyway recommend building a single 3 axis board rather 3 single axis boards. Right now i have a 3 axis board with one blown chip, which basically means the whole thing is useless to use on the mill. If i had built the 3 single axis boards then all i would have to do is build one more board and then go from there. I used a 12volt supply and 10ohm 10watt resistors and didn't have any problems until the heat sink fell off. If you goto 24volt make sure that all your capacitors are rated for it. I had to change 2 on the board i had due to they were only rated for 16 volt.