RE: [CAD_CAM_EDM_DRO] CAM Software and Hardware

Hi, Zorad:

Sadly, you don't really provide any information in your note to allow us to
provide some insight into the cause of your problems.

Several of us are running Sherline mills under CNC, and are probably using a
host of different hardware and software combinations to drive it, all
successfully.

My personal system consists of a Sherline 2000, Sherline's motors (because I
wanted double ended shafts on the motors), Camtronics 2 amp drivers, an old
Zenith Notebook (486DX2-50, 8 Mbytes), and TurboCNC as my G-Code
interpreter. I'm able to run about 4000 steps/second on two axes and 2600 on
the third. Reliably. This is somewhat faster than 3 IPM, which is what your
1 inch per 20 seconds works out to be.

Question - What operating system are you running under? If it's windows, be
aware that the Windows overhead prevents any program from producing a nice
evenly spaced pulse train to the motors. An uneven pulse train at high
speeds causes the motors to stall.

Question - Are you using bipolar or unipolar drivers? If it's unipolar, be
aware that these will seriously affect performance downward.

Question - What is your power supply voltage? Most of the CNC systems start
with power supplies of 24 volts and work up from there. If your power supply
is close to the rated voltage of the motors, performance will suffer. You
don't need a regulated supply, but you do need the voltage.

While Sherline tools will not give you the performance of a large mill with
5 tpi ballscrews, it is capable of doing good work as long as you stay
within its work envelope. Fortunately, that work envelope is larger than the
speeds that you indicate.

As you start, don't worry about making a part. Think more of simply moving
the motors on each axis using the MDI (one instruction at a time from the
keyboard) mode of your G-Code interpreter and work with the system until you
get acceptable speeds. Then, start worrying about making G-Code. I use
VectorCAD/CAM as my drawing and G-Code generating program. It's well worth
the cost, IMHO. Or, you can start for free with something like Intellicad
and YeagerAutomation's ACE Converter. You'll have to do a lot more work for
pocket holes, etc, but you can generate G-Code with it.

Hope that this is a start.

-- Jerry


|I recently hooked my Sherline up for CNC with hopes of doing amazing
|things with it and have been pretty disappointed thus far. The
|steppers only run about one revolution per second at best, which, if
|my math is correct, is about 1 inch per 20 seconds. Even at that
|rate they are not smooth and jerk terribly. The software doesn't do
|what I would think are basic necessaties. For example I would really
|like to be able to do some sort of looping so I could just change one
|axis of a cut and do it over and over to achieve the desired cut
|depth or distance. Current method is write the first path then cut
|and paste then go back and change the moving axis for each path.
|Tedious and creates a potential for failure. Also, although it says
|it does cutter radius compensation I can't seem to figure it out. I
|have scoured the internet for info on CNC programming and suprisingly
|I find very little. I am a computer geek by trade and have a strong
|mechanical, electrical, drafting, CAD, and programming background but
|this is kicking my bu#@.
|Sadly thus far my CNC milling has been reduced to very slow running
|of extremely simple tasks. Basically letting it do the same simple
|routine over and over so I don't have to turn the cranks but
|certainly not doing anything 'elegant'.
|In reading some of the emails in this group I have a feeling my
|configuration my be unique or I am doing something wrong as I'm
|seeing people boast of unbelievable speeds and some pretty impressive
|accomplishments. Do I need to scratch my purchased $1000 package
|config and follow a proven homebuilders recipe?
|
|
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