Building My First CNC Router, Looking for Advice & Other Info

**AlexDoran** · 20-10-2017

By pure luck i have managed to find some rather nice (and expensive Balluff Brand) Proximity Sensors in my brothers shed (He is the maintenance guy at work), he only had 4, which is ok as it means i am able to the machine homed, and perform some more tests, and actually - im not sure that i even to have Max Limit Switches? There is a Software Travel Limit that is defined and seems to work very well, im not sure if these get ignored when running a program so i will have to check that out.

However now i can only seem to get the Z Axis to move in one direction, i was thinking that it must be a loose / funny connection somewhere since i had been tidying all of the wiring up. However if there was a problem with the wiring would the Stepper even move in one direction at all?

I was also curious as to how the Axis should be orientated, currently the X (my longest Axis) and the Y both home to minimum - Position 0, and then move positively through the co-ordinates- for example 0 -> 1010mm. However i know that our big machines move negatively, eg: 0mm -> -3000. Is there a standard way of setting this out? What are the implications, do they just affect how you need to setup any post processing configuration from SolidCAM, Fusion etc?

Im also curious about how the Z Axis is orientated too, when moving positively it travels upwards - the homing is set to minimum but when homing it searches upwards. Possibly this is because of the problems i am having with the Axis.

Thanks

Alex

**Clive S** · 20-10-2017

Im also curious about how the Z Axis is orientated too, when moving positively it travels upwards - the homing is set to minimum but when homing it searches upwards. Possibly this is because of the problems i am having with the Axis.

Thanks

It is usual to have the Z showing -ve going down so +ve and home would be at the top. The other two are personal choice.

Re the Z only moving in one direction check the (dir) on the driver and make sure it is changing sense ie 5v and 0v

**AlexDoran** · 20-10-2017

Originally Posted by Desertboy

Nice one both you and Clive tested my spindle today with an ammeter and it's obviously pin 4 is not connected to anything ;)

Will do as Clive suggested, were the top bolts hard to undo? I tried and felt some resistance like I have some loctite to break didn't want to push it until I asked had a nightmare rounding off A2's next time I build I will only use A2's were needed and stick to proper bolts if appropriate.

I had to crack them, think there was some thread lock on the bottom of mine, i one exactly as Clive suggested. However still cant seem to get the spindle going - have not tried today however; might switch it back to manual configuration and run it directly from the VFD just to make sure that everything is wired correctly.

Originally Posted by Clive S

It is usual to have the Z showing -ve going down so +ve and home would be at the top. The other two are personal choice.

Re the Z only moving in one direction check the (dir) on the driver and make sure it is changing sense ie 5v and 0v

Ok, well i guess it makes sense to change the X & Y to follow suit (Move Negative AWAY from the Home Position). At least then they are all the same and i can't confuse myself - which is very likely.

Roger Roger - Will check that thanks Clive.

Alex

**Clive S** · 20-10-2017

Ok, well i guess it makes sense to change the X & Y to follow suit (Move Negative AWAY from the Home Position). At least then they are all the same and i can't confuse myself - which is very likely.

If it was me I would keep the x and y going +ve away from the home switch. but still have the Z going down -ve as it is easier to read the gcode

**Neale** · 21-10-2017

However, it is possible to have (0,0) in, say, the "bottom left" corner, which tends to be natural when you are standing in front of the machine, but have the home position in the top right corner and set the home position to the max value of travel. This gets the tool out of the way when you home. Or you can have each axis home at min or max. It's a question of choice. It's easy enough to configure Mach3 for each situation.

**AlexDoran** · 23-10-2017

Thanks guys i will have a think about it.

Alex

**Jerm** · 25-10-2017

Hi Everyone,

I'm glad someone is taking the time to elaborate on my design. ;)

Although not much use to you now, I've been meaning to make the CAD files available for others to use, perhaps I will get onto that this week.

I'm interested in seeing how your machine performs with 10 mm pitch screws. I used 1605 screws and have found them perfectly fine for my requirements. I've seen others online stating that 5 mm pitch screws are too slow and I fail to understood this statement. A machine this size which isn't used for production purposes I didn't see the need to maximise rapid speed. It's fast enough as it is! Perhaps a full size machine would require more speed, but then i'd probably move to rack and pinion anyway.

I too prefer "home" the machine to the back right hand corner, this means that the gantry is at the back and out of the way after initial startup, ready for me to load a sheet of material onto the bed. I have the axis set up as X from left to right (gantry) and Y (dual motor drive) front to back when standing in front of the machine. Therefore my homing position is X+,Y+,Z+.

I look forward to seeing some test cut footage on this machine!

Cheers
Jeremy