I've been vacuum laminating shop-sawn veneers for six years using a Robin Air 15300, 3 cfm pump which lasted 5 years, pulled 29" Hg and was very fast on a small bag. I did not change oil after every use as recommended and condensation in the oil finally killed it. A very good pump, I thought. I then replaced with an upgraded model 15500 5 cfm Robin Air and this pump failed in just two weeks. I got a quick replacement on warranty and this replacement started blowing smoke and lost vacuum in only 4 hours use. Ten days later, the mfgr. has yet to answer my warranty claim. The last two pumps had an issue of blowing out vaporized oil smoke; the first one didn't. Further, out of 463 reviews at Amazon, 95% are highly favorable. Robin Air is a product of Bosch Tool.
This leaves me with a dilemma. Do I consider my two pump failures as just a matter of very bad luck and not likely to happen again and order another one? This type of rotary vane pump is the lowest priced type but they do have smoking problems AND they all (MasterCool, etc,) seem to be made by same mfgr in China. Diaphragm pumps, (Gast) which do not smoke, cost 4-5 times as much and are much lower volume. To pull 6 cfm at 29 hg. i'd pay close to $1,000, much more than I can bear. There are lots of other options in teh 1-2 cfm range. At 5 cfm my pump pulled a full vacuum in just one minute, and since thers is no auto-cycle, I have to manually fire it up 3-4 times to maintain a vacuum for one hour, the time it takes my glue to set up in my operation using hard 1/8" veneers (the less porous the wood, the longer the set up time). My need for fast draw, high pressure, low cost suggests I should take another chance with Robin Air.