Cold CNC Machine Won't Run

When a CNC device generates a "too cold" error message after spending the night in an unheated shop, pay attention. March 6, 2006

We don't heat our shop overnight. As a result, we sometimes get an error when we start up our Homag BOF 711, saying that it's too cold to operate. We sometimes have to wait 45 minutes to an hour for the error to clear so that we can run items. Does anyone have a solution?

Forum Responses
(CNC Forum)
From contributor A:
How cold does your shop get? Maybe you should consider just reducing your temperature instead of turning it off.

From the original questioner:
Unfortunately, there is no reducing of temperature option. It's either on, or it's off. And since we only run one shift, it's off most of the time. It probably gets down to the mid 30s out in the shop.

From contributor M:
Try putting a timer on your heater to automatically turn on an hour or so before you open the shop in the morning.

From contributor R:
Find out where the sensor is for the machine and put an electric oil heater (the ones that look like a small radiator) near it. This could be on a timer to turn on early in the morning and provide enough heat near the sensor to fool the machine into thinking it's time to go to work. Make sure you do an adequate spindle warm-up before you start cutting.

From contributor M:
Contributor R, that is a *very poor* piece of advice to offer. There is an obvious reason the machine gives the message "Too Cold to Operate". The grease and oil are too cold to flow properly for lubrication. If they can't flow, parts will wear prematurely and the machine will fail with significant repair costs to follow. Many newer machines have a warm up cycle on them. It will start out with very low rpm's and very slow motion. Gradually the rpm's will increase and motion will speed up. This takes 5-15 minutes. It gets the machine warmed up and lubricants flowing.

From contributor B:
Turn up the heat! Like the post above says, you are - without a doubt - going to break or prematurely wear out many of the moving components on your machine. Generally speaking, if your machine is smart enough to know that it is too cold to operate, chances are that it cost significant dollars. Look into an alternative method of maintaining temperature in your shop. You will save money in the long run. Replace a $7000 spindle just once and you'll wish that you had kept your shop at a temperature that the machine can withstand without issuing a "too cold" alarm. Of course, the oil/gas/electric companies will like you more, too.