Mach 4 greyed out after clicking home or keyboard jogging

So we’re just getting the CNC set up at our shop and I’ve noticed an error in the morning sometimes when I started up. I’m making sure to turn on the CNC and let it boot up before starting Mach 4. But as soon as I click the home button to home the machine, everything is greyed out. When I click one of the keyboard arrow keys to jog the machine and get it ready everything grays out.

I believe the cause of the problem is the error messages that I get when opening Mach
four. The photos attached.

Any advice, help, Suggestions are greatly appreciated. I need to get this machine up and running because production is slowing down for it.

Could be something simple like the last person to use it is parking the X axis up against the limit sensor before they shut down.

However, since you said you are just getting the machine going, I would recommend going through your sensor and soft limit setup thoroughly to make sure they are all in the right order and have a little margin between each other. Here is a video on that
The guy is pretty boring to listen to, but it might be helpful :slight_smile:

@jjneeb is probably right.

In the winter your machine will contract and the sensors you set while the shop was warm can be off.

I have a heater specifically set up for my machine and it runs all winter.

It got so cold down here in Georgia that the metal shrunk enough to pull the splices on my side rails apart by about 1mm. Probably because it was assembled in the high 90s F and then it’s -13F for 3 days straight. Sounded like a large firecracker going off when I started the machine up and started homing.

I imagine the opposite would be true for people putting these things together in cold places.

Thats funny. I had a problem when it got to 100 degrees here with the plastic dust covers over the rails buckling up when they expanded. Aluminum, Steel, and plastic have such different coeffients of thermal expansion, and it seems most people are running these things in uncontrolled temp environments, I’m actually surprized we don’t hear about more of these kinds of problems.

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Blame it on the WiFi :rofl:

You are 100% correct. I too wonder about things like clipping the Z limit after a 1hr long run on a sheet of baltic birch.

And it didn’t hit it either! It zero’d fine but 20 minutes later it triggered the limit switch. Just sitting there…

Cooling off…

Just in case anyone is interested, an 8ft aluminum extrusion will grow almost 0.090" for a 70 degree change.

Steel is about 2/3 that, so now I’m wondering if the gantry warps over temp (because with the linear bearing rails bolted on tight, thats bascially a huge bimetalic strip).

Has anyone measured their gantry straightness across temp?

I had not considered the steel linear rails bolted to aluminum extrusion. The Z axis system is also aluminum with steel linear railing. And, as you pointed out they grow and shrink at different rates with temperature.

I have been recording temperature with my OpenLog so that might give insight at some point.

Just for giggles I put a dial indicator on the center of my gantry this morning and zero’d it and put a thermometer on top. Everything was stable at 70 degree or so. Then I opened my garage doors and let the cool air come in. After stabilization I was at around 60 degrees and the center of the gantry moved about 4.5 thousandths.
Not a super precise experiment since I didn’t have enough indicators to make sure the ends of the gantry didn’t also move, or that my dial indicator arm wasn’t affected by the temp change as well, but things definitely did move. My gantry is a 4ft one.