Thursday, June 14, 2007

The Hammer and Pry Bar Incidents

HammerAs with any CNC machine, and Excellon is no exception, it is wise to make sure operators keep the hammers and pry bars away from the table tops.

Operators seem to continually try to challenge the structural integrity of the machines by placing tools on top of the tables or in the path of machine carriages and powered XYZ assemblies, and then decide to hit the park button or typing a high speed jog command into the keyboard. Loud thumps can be heard clear across the production floor. More than one machine has taken a crash over the years. Actually, this type of crash is a very common occurrence in the life of a drill and rout cnc machine. Even cnc milling machines and other types of automated servo controlled equipment and robotics have been known to take a hit or two from someone leaving a tool on the table or getting it wedged between the XYZ moving parts.

Excellon Mark VIWhen the Excellon drilling and routing machines only had spindles to contend with, on the z axis overhead assembly, a crash was much easier to deal with. Simply placing an alignment pin in the nose of the spindle and going to the magic number locations to see if the spindle was out of alignment for tool changes was the thing to do. However, with the advent of multiple tool magazine holders, a crash involving the tool cassettes requires substantially more work to verify the alignments of not only the spindle, but also the alignment of the tool magazine assembly and the transfer piston assembly.

Other precision hardware components can also end up heading for the trash can when a crash of this magnitude occurs. For example: key pressure feet components, used for precision depth control, have been known to become bent and inoperable. Many of these incidents can result in excessive down time, expensive part replacements, and time consuming service calls.

Make it a drill room policy to remove that hammer and pry bar from the drill table before the machine is moved. Better yet, don't place it down on the drill table surface to begin with. Your machines will appreciate implementing this policy plus the company will not have to pay for as many service calls. The bean counters will love it, we guarantee it.

Contact Probe Industries, Inc., Your Machines' Best Friend

Addendum to the Story

In recent news, was a machine that the operator left the hand tools on top of the granite surface and proceeded to hit the park button, jamming the tools against the front cover and underneath the table top. This caused one of those loud thud sounds in the drilling production room, and also lifted the table several inches above the proper position. Several precision air shoes popped off their mounts. However, this was not the worst of the problems.

The y axis Heidenhain scale was crashed. The read head encoder portion of the scale was bent in the middle, and the machine alignment blocks were knocked out of alignment. The machine was KO'd for the count.

Several thousand dollars latter in new parts and labor, along with some extensive rehab time were necessary to get this machine rolling along again.

So, be careful where you place your tools.

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