Lube pump

[TarHeelTom]

In the tail end of getting a new computer (D510MO) ready to install in the Bridgeport.

The Bijur pump was bad, and the repair cost was way too high, so bought a Taiwan made clone. It's a clockwork type lube pump, very similar to the Bijur, which fires off a single shot of oil once every 30 minutes. So basically, it needs to be powered anytime the table is in motion.

Ran into Matt Shaver at the recent cnc seminar, and he showed me one method of powering the pump whenever the table is in motion. After much searching through the EMC2 docs, he found a "velocity" signal, which is probably the float variable which is sent to the DRO in AXIS. He compared that to zero, and added a small hysteresis, then sent it to an output pin. I'm using an ac relay to power the pump, so had to invert the output line. Your needs may vary.

Here's the code:

# Let's pick up a signal to turn on the lube pump

# Original code work by Matt Shaver
# Add a comparator component 

loadrt comp count=1

# set the hysteresis to a small value to

# allow for very slow movements before turning on the pump

setp comp.0.hyst .01

# The first input to the comparator is zero.

setp comp.0.in0 0.0

# The other input to the comparator is the

# current axis movement velocity

net moving comp.0.in1 
motion.current-vel

# This signal is the output, but is inverted for my puposes YMMV

setp parport.1.pin-16-out-invert 1

# It needs to be connected

# to an output bit

net pump comp.0.equal => parport.1.pin-16-out 

# We need to run the comparator periodically

addf comp.0 servo-thread

Enjoy, and hope this helps someone.

Tom

[TarHeelTom]

Matt's routine to turn the lube pump on with movement, seems to have worked well. One possible complaint might be that it sometimes seems to stay running after a cnc program has finished running.

But I'd rather have too much oil than not enough.

However, when the one shot oil pump would fire, it would always make a bang when the piston hit bottom. The oil pressure gauge would bounce up to perhaps 10 psi and quickly return to zero.

Couple of days ago realized that I hadn't heard it bang lately.

Tonight I wrote a short cnc program to move the table full travel left and right, and a little front to back, at about 0.75 ipm, but without the spindle running.

Then sat there for about 20 mins waiting for the pump piston to drop. I'd installed a remote oil pressure gauge on the throat of the mill. All of a sudden I noticed the oil pressure was at 50 psi, and then took a min or two to drop back to zero.

Which is how it SHOULD look every time the pump cycles.

Finally decided that we induced a lot of air into the oil lines while we had the mill apart replacing the 32 lube metering units. It has taken many days of operation to finally work all the air out of the lines.

In the future, any time I disconnect an oil line for any reason, I'm going to power up the oil pump with the mill not running, or only running occasionally, and give the pump plenty of time to purge all the air out of the lines.

Tom

[PCW_MESA]

Originally Posted by TarHeelTom Matt's routine to turn the lube pump on with movement, seems to have worked well. One possible complaint might be that it sometimes seems to stay running after a cnc program has finished running. Tom

if you set the threshold to some small positive value greater than the hysteresis like:

setp comp.0.in0 0.02

it should stop when motion stops

[TarHeelTom]

Originally Posted by PCW_MESA if you set the threshold to some small positive value greater than the hysteresis like: setp comp.0.in0 0.02 it should stop when motion stops

Thanks, I'll give that a try.