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Give Equipment Cooling an Upgrade

Effective cooling of equipment can be absolutely vital to its longevity. In this short post we take a look at upgrading the cooling fans on the control cabinet of a CNC plasma cutting machine.


A number of years ago we purchased a budget CNC plasma cutter and while this was of fairly solid mechanical construction, much of the control electronics left something to be desired. So back in late 2015 we embarked upon replacing the electronics and while we didn’t replace the cooling fans, we did replace the simple grilles without filters, with fibre filters (050-7905) . The last thing we wanted was small particles of metal and carbon getting sucked into the control cabinet!

Despite the machine getting only very occasional light use, as can be seen in the photo above, fitting filters to the fans was clearly a good move and they’ve proved effective. However, fitting filters will have obviously impeded the airflow — by between 10 and 30% according to the datasheet — and given the open louvre vents at the opposite side of the cabinet, a good positive pressure inside it is desirable in order to help prevent ingress of particulate matter during cutting.

In addition to the above consideration, the bearings on one of the fans had started to become noisy and so now seemed like a good time to replace the fans with new, higher performance parts.

Fan selection

The original Sunon 2112HSL fans are quoted as having an airflow of 2.01 M3/minute, so we decided to aim for a replacement with closer to 3 M3/minute. This should give us plenty of margin when it comes to the accounting for the reduction in flow caused by the fibre filter.

After looking at the available 119mm axial flow options, it was decided to go with an ebm-papst part from the ACi 4400 Series. While the high energy efficiency these offer via use of EC technology was not a key consideration, the stated low noise and long service life appealed.

With an airflow of 3 M3/minute, the ebm-papst ACI4420HH part (740-6398) was selected. Two 2.8x0.5mm plug and cord sets (826-1329) were also selected to enable the fans to be cabled up.


Here we can see one of the fans fitted and at 38mm in height compared to 26mm, these are taller than the original fans, but there is still plenty of room in the cabinet.

Finally, the synthetic fibre filter media (118-6133) was replaced in both fans.

This simple upgrade should help to provide continued, reliable operation of the machine.

Andrew Back

Open source (hardware and software!) advocate, Treasurer and Director of the Free and Open Source Silicon Foundation, organiser of Wuthering Bytes technology festival and founder of the Open Source Hardware User Group.

4 Aug 2017, 9:44