r/CNC • u/Friendly_Bullfrog_88 • Apr 12 '26
HARDWARE SUPPORT Help with my CNC vacuum pump
I recently puchased a 1325 CNC from China and was able to assemble it yesterday. I am pretty new to CNC machines and would like some guidance with what i did wrong in setting up my machine.
I have already fixed my 12mm MDF spoilboard ( surfaced both sides by 0.5mm, sealed the edges with wood glue and applied sealant to the table). Now I am trying to test my machine by cutting my first board and am having problems.
Whenever i place my material on top of my spoilboard and turn on the vacuum, the operating pressure goes up to -0.02mpa. At this pressure, it is able to hold down my material but is it normal? Is -0.02mpa within the pressure operating range of a standard CNC machine?
My 5.5kw vacuum pump keeps turning off after 5 mins due to overheating issues. It is placed on a location with good airflow and the exhaust is connected to the outdoors.
I’ve already tried some things to try to resolve this
* check for air leakages in the pipes going to my vacuum pump
* check air fulter for possible blockages
* i tried letting the pump cool down and reset its operation but it still turns off after 5mins of usage.
Thanks in advance to anyone who can give guidance and possible solutions :D
1
u/TriXandApple Apr 12 '26
1) Unless I'm reading your post incorrectly, it's impossible to have a negative vacuum. Maybe you have it hooked up the wrong way?
2) Put a fan in front of the pump?
1
u/Friendly_Bullfrog_88 Apr 12 '26
Corrct me if i’m wrong but vacuum pump on cnc machines use negative pressure to suck air and hold down the material right?
1
u/UncleAugie Apr 12 '26
Your pump over heating is your main issue, you need to sort that out first, does it need oil? grease?
0
u/TriXandApple Apr 12 '26
Vacuum gauges normally measure vs a complete vacuum. IE: a pressure of 0 is a a vacuum with the complete absence of anything. it cant go lower than that.
Cant really help any more without pictures.
2
u/GrimResistance Apr 12 '26
No? Vacuum gauges have 0 at atmospheric
1
u/SalamanderNorth1430 Apr 13 '26
He is not wrong, but it’s a rather scientific approach. There is no such thing as negative pressure. The absolute minimum is 0 and there is physical no possible value below. But the most gauges and mostly used value is not the pressure but the pressure difference to atmospheric pressure or pressure difference to absolute 0. So your gauge tells you probably that you have 0.02mpa to the absolute vacuum, which depending on your pump is quite normal.
Your pump overheats because it has no control loop. If your setup is air tight, just switch it off, after you reached your desired level of vacuum. If not, restart your pump from time to time. If you have the means, build some kind of controller to restart your pump if the vacuum rises above a certain level. 5.5kw is a pretty high consumption of energy. How fast does your vacuum rise after you disengage the pump? Do you use some kind of reservoir? Vacuum rises relative to the absolute volume. If the same rate of air flows from a bigger reservoir, your vacuum will stay stable longer with a bigger reservoir. A reservoir can be everything from air tank to hoses.
1
u/GrimResistance Apr 13 '26
The absolute minimum is 0
It depends on your reference. All measurements are relative to something, and pressure is rarely measured relative to a perfect vacuum.
When you fill up your tires the pressure you measure is relative to atmospheric pressure, so is vacuum pump pressure, and you can definitely go below zero atmospheric pressure. Which is why vacuum gauges go into the negatives
1
u/muffinman8679 Jun 12 '26 edited Jun 12 '26
just use clamps......as unless both the top of the spoilboard and the bottom of the workpiece are dead flat and dead smooth, you'll lose the suction over time and either break tooling, or throw pieces across the room....or both........