Hello Guest it is October 26, 2021, 07:11:44 AM

Author Topic: Just bought my first cnc, need some pointers/info please about getting started.  (Read 10353 times)

0 Members and 1 Guest are viewing this topic.

My name is Chad, I'm builder in Maine who is looking to start learning mach3 and cnc.

I just purchased a cnc router from ebay, http://cgi.ebay.com/40-inch-cnc-router-engraving-milling-machines-/270775652255?pt=LH_DefaultDomain_0&hash=item3f0b7c8f9f and im thinking about picking up a laptop to use with it.

This is the laptop I am checking in to and was wondering if it would be ok? http://www.staples.com/Toshiba-Satellite-L775D-S7222-17.3-Laptop/product_331466
 I also believe I need to get a parallel port adapter? Would this work?  http://www.staples.com/Belkin-USB-Parallel-Cable-Adapter/product_382233

I'm still getting my feet wet with the whole cnc learning process. I should of done more research before jumping in and buying a machine but, you only live once and home cnc machines look like a blast to mess around with. DHL is due to drop off my new cnc machine any min now and I will post images and videos when I get it for those interested.

Also, I have been skimming through a lot of newbie questions and have yet to find any video tutorials for basic/first time user help. I have seen calibration, and other steps but none really for hardware hookups. Does anyone know of any such tutorials or does every machine have completely different configurations?

Thank you in advance,


Offline Tweakie.CNC

  • *
  •  8,835 8,835
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Hi Chad,

Welcome to the forum.

Not a good idea to even consider using a laptop (power saving features can screw up Mach operation) and that parallel port adapter will just not work with Mach anyway. You really need a dedicated PC with a parallel port and a separate graphics card (I bought mine, second user, for about £15 GBP) It does not need to be anything special.
The official line is;
*You must use a Desktop PC running a 32-bit version of Windows if you are using the Mach3 Parallel Port Driver. Laptops are not supported because the power saving features of the chipsets disrupt the pulse stream. Mach3 will only be supported on laptops running an external motion controller, such as one of those found on the Plugins page.*

There have been mixed reports on that particular CNC machine so you may have to do a little work to get it all working as it should but it is a good start and there are plenty here who will help any way they can.

Did you get any instructions etc relating to which pins relate to the step and direction signals from each axis ?

Ok, I got a base partially made. Still need to add plywood to strengthen it up some but the machine is mounted. http://enolamron.com/stuff/images/cnc/base.jpg

I took your advice Tweakie and I am just rebuilding a pc I had laying around that already has win xp and parallel port. It just needs a new vid card and maybe some ram. I also need to do some research on limit switch mounting and wiring. I remember seeing a video somewhere. Now just to find it.

Items my machine came with are as follows:

Limit Switches http://enolamron.com/stuff/images/cnc/limit.jpg

Transformer for dremel tool thing(not sure if it is needed.) http://enolamron.com/stuff/images/cnc/transformer.jpg

Control box [img]http://enolamron.com/stuff/images/cnc/backbox.jpg

Cable http://enolamron.com/stuff/images/cnc/cable.jpg

I think these are the t-slot clamps? http://enolamron.com/stuff/images/cnc/clamps.jpg

Only doc that came with it is.  http://enolamron.com/stuff/images/cnc/setup.doc
I skimmed the instructions and they look fairly complete.

Note that the kernel speed should not arbitrarily be set to the max, 100kHz. It should be the lowest possible setting and varies with your max motor speeds. Actually, to be technical, the kernel speed required is determined by the actual number of pulses per second required to drive your motors at the selected maximum velocities. It is also affected by the resolution set on the motor driver.

Basically, you could work through the calculations, or just set it to 25kHz and bump it up one level at a time if it says the kernel speed is too low. I run my table at a high resolution (can't remember off hand what it was, but max on the controller) and have max velocity of 130 inches per minute, and a kernel speed of only 35khz. I can't see your machine requiring more, but rather 25kHz will likely work just fine.

There's no point in setting it higher than required. Higher kernel speeds have the potential for reduced reliability.

Also they recommend a laptop, and as Tweakie already mentioned it's not a good idea.

There may be more that's a little bit off, or maybe not quite the best way, but it should give you a pretty good start and you can learn from there. Hopefully there's enough in there to get you up and running!



Offline Tweakie.CNC

  • *
  •  8,835 8,835
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Hi Chad,

Just a couple of additional points, from looking at the instructions;

The Z Axis is conventionally set up so +Z is upwards, away from the work and -Z is downwards towards the work.
It is usual to have the long Axis as the Y Axis and the short Axis as the X Axis.
You would be wise to use Shielded cable for the limit switches and ground the shields to the metal casing at the controller end only.
The instructions indicate that your power input is  110 Vac and that the supplied spindle is 220 Vac so there is a 'step-up' transformer to create the correct voltage for the spindle.


Offline ger21

  • *
  •  6,293 6,293
    • View Profile
    • The CNC Woodworker
Basically, you could work through the calculations, or just set it to 25kHz and bump it up one level at a time if it says the kernel speed is too low

Just a note that Mach3 will not tell you if the kernel speed is to low. Unless, you set up the motors with a higher kernel speed, and then changed it to a lower speed.

If you're accel or velocity settings in motor tuning are as high as they will go, that is what tells you to use a higher kernel speed.


2010 Screenset

JointCAM Dovetail and Box Joint software
Thanks all for the help.

Today my plan is to get the pc all set up with mach3 trial software, get my limit switches wired and mounted and do a little more work to the base.

Thanks again,
Hello again,
Pc is all set up and got everything but the limit switches and cutting tool finished. I am able to control the motors with the jog buttons. Putting the motor outputs the way that was listed in the instructions had my z axis as y and y as x. They were all messed up. I changed the step Pin and Dir Pin so now when I press Z+ the tool moves up and also change the X for short and Y for long movement. Does this matter I changed the motor outputs to fix it?

I ended up buying a new router which with a little modifying I can use the same bracket to mount it. http://www.lowes.com/pd_226729-353-PR20EVSK_0__?productId=1062825&Ntt=router&pl=1&currentURL=%2Fpl__0__s%3FNtt%3Drouter&facetInfo=
Does this look like I good tool to use?

Now this leads me to a couple more questions about the picture below. Do I need to hook the router to the control relay or can I just manually turn it on? Also the top limit switch has me confused. Is that for a home switch or something? I don't see it in the doc unless I am just missing it. I'm only seeing 6 switches in the instructions but I did receive 7 switches with my machine. No idea what the +30v connection is used for in the picture either.

Thanks again.
I would have done the same to fix the wiring issue.

The router can be controlled via manual switch or the relay according to the diagram, you're choice.

Top limit switch for Z is indeed for homing and can also double as an upper limit of course. Also note you can gang all the limits together into one input if you'd like, freeing up a few more inputs for a gage block/edge finder/probe/etc.

Is the 30V the input power for the motors?

Top limit switch for Z is indeed for homing and can also double as an upper limit of course.
So I can eliminate the top limit switch in the picture, I think is says C where it is plugged in to and just use the Z limit switch for both home and upper limit? So only a total of 6 switches need to be wired?

Is the 30V the input power for the motors?

That must be what it is. I didn't notice before but the it has two wires already coming out and going back in to the box. Photos below of the wires and limit switches.