Death of a Vacuum

It was almost 4 months ago to the day, that I built a vacuum table for the CNC router.

While it worked well, I was sure the lack of overall airflow would result in the vacuum carking it very quickly.  Job after job, and it kept going.  It was encased in a rubbish bin with noise absorbing material stuffed around it to drop it’s horrendous noise down to bearable levels (it was a ShopVac, and it always was a screamer). It ran warm- the exhaust was always hotter than was healthy.

Went out to the shed tonight to check on a job, and although the CNC has indeed finished, it was a lot more silent than usual.

Instead of the muffled sound of the vacuum, there was a familiar smell of burnt plastic and ozone.

Carefully switching it off then unplugging it from the wall, I went on dealing with the job at hand, and then went over to the garbage bin, and started unpacking.  Partway down, and the normally white insulation material started coming out black.  Desite being some time, the vacuum itself was still very warm.  A complete meltdown.

Not as bad as the last vacuum though.  Years ago, I had a household vac for dust extraction, and it also failed in spectacular fashion, actually melting until it literally fell apart, and the motor fell out of the housing.

So the machining tonight has stopped, slightly prematurely.  I haven’t added up the hours the vac did in those 4 months, but it would legitimately be into the hundreds of hours.  Hundreds of hours, in a MDF laden atmosphere, with poor airflow. I think it did a pretty good job in the end!  Not even sure what the designed duty cycle of the vac was, or the model’s MTBF (mean time between failure).

So now the decision is “what next”?

Another cheap vac?  A vacuum pump?  If so, which one?  There’s a bunch on eBay, all different cfm, and I have no idea what cfm I’d actually need, let alone my current table would leak like a sieve, so would never actually be able to maintain a vacuum.  And that means the vacuum pump would be running continuously, unless I make some real mods (rebuild) to the table itself.  What do commercial machines do for a vacuum table, and the pump for them?  Too many questions, not enough answers (yet).