VOL. 15 July ISSUE YEAR 2014

MFN Trainer Column

in Vol. 15 - July Issue - Year 2014
Maintenance of Shot Blast Machines
Shot blast machine

Shot blast machine

Branko Cvetkovic

Branko Cvetkovic

We all have ideas what maintenance means. To clear things up, I went online and checked the Webster dictionary for a definition of maintenance: the act of keeping property or equipment in good condition by making repairs, correcting problems, etc. I also checked the definition of the maintenance worker: a worker whose job is to keep property or equipment in good condition. Two very simple definitions
Do the exercise: if you work for a small or large company, have two maintenance techs together for coffee and start asking questions about maintenance of a single piece of shot blasting equipment that both are familiar with. The first 5 minutes of the conversation will be in general agreement, as more time passes by, a heated discussion will develop. Those two guys will not talk to you and each other probably for a week.
Those two guys are from the same company, same area, same state, same country, and still cannot have agreement or common position on maintenance issues. Now, do another exercise: get a maintenance tech from Alberta (Canada) and maintenance tech from Texas (USA); you might not need 5 minutes at all to develop a heated discussion over the same maintenance issue, on absolutely the same machine they have in production. Very recently, I was in Germany for a business trip, and I spent a week with an OEM that manufactures mass finishing (vibratory finishing) as well specific shot blast/peen type machines. Fortunately, they did take me to see their shot blast machine in action in several companies. We visited a company that uses machines for deburring and cosmetic finishing of the forged aluminum parts. As usual, I went straight for the work hour counter on the main electrical panel (professional deviation). It was slightly over 20.000 hrs on counter. The machine was in excellent condition. Second visit was to one of the oldest tool manufacturers that have 3 machines and use machines for post forge (steel) blasting operations ¡V descaling. Again, I did check work hour counter on all three machines; the first two did have 18.000 + and 33.000 + hours. The third one and the oldest in appearance recorded only 12.000+. All three machines were the same type, but for the oldest one, you could see some difference and how the design was improved on newer models, still, it was basically the same machine. I had a somewhat puzzled look on my face, and their maintenance manager (I can swear he was 6¡¦4¡¨ and look like Arnold Schwarzenegger) told me that machine was almost 20 years old, and had turned the clock 2X!!!! We all know (I presume) what a machine located in post-forge operation should look like. This machine was in absolute good work condition (currently running production). I checked vibration on blast wheels (4) and I was allowed to climb to see how the air wash worked. I could not see the blast chamber inside (production was running), but I looked for welded patches on the outside shell of the blast chamber and could not find a single one.
I have a single conclusion: any company that has shot blasting equipment shall hire a maintenance manager who is not less than 6¡¦4¡¨ and is built like Arnold!
I live in Canada, on the border with the USA. I do travel extensively through both countries visiting plants that have shot blasting equipment, and I can tell you how blast machines with 200.000 work hours look like in NA. There are some exemptions, but they are rare on machines that are in use in production for 20 years+. We cannot blame maintenance only for the state of the shot blasting machines. There are many factors that dictate and influence why we do what we do (or not). I believe that from the recent downturn (2008/9), maintenance of shot blasting machines in NA is going in a positive direction. We quickly realise that machines can last longer, do more, if we take care of them. Machines need to be maintained not only on Saturday or Sunday, but any day in the week. It is hard to schedule downtime, and there is a constant fight between production and maintenance. I know that OEM of shot blasting machines provide operational and maintenance manuals to end users, and that is a must. I just wish that they used pictures that clearly show the consequences if something is not done on time/schedule as should be. We are all visual learners. If you smoke, a picture of mouth/throat cancer on a cigarette package will have some result on your thinking of a future state of your health.
Or, maybe we should hire Arnold.

For questions contact: branko@mfn.li

Author: Branko Cvetkovic