First published in the August 1997 issue of Cutting Tool
Engineering magazine.
When Feasible, Be Consistent
Be consistent with your corporate goals and company profile
Earlier we introduced many of the factors that contribute to your company
profile. The most serious waste-causing inconsistencies are those related to
your company’s corporate philosophies and goals. Here are a few wasteful
examples.
Company location - A company that is located in a rural area (having
a very limited manufacturing base) unwilling to train newcomers.
Lot sizes - A company that commonly runs medium to large lot sizes
and lots of repeat business (ample time during the production run to prepare
programs) might expect their CNC operator to program every job during setup
with conversational controls. This kind of company would benefit from
programming off line. Just the opposite is true as well. A company that has
several CNC machines running small lot sizes and no repeat business (no time to
program off line) might have one programmer trying to keep up with all
machines. This kind of company would benefit from shop-floor programming.
Just-in-time - A company that is expecting to achieve just-in-time
might be unwilling or unable to invest in adequate CNC accessories to fully
achieve the goal.
Cell versus stand alone machines - A company that applies cell
concepts might have limited similar processes that might make it wiser to apply
stand alone CNC instead of cells.
First workpiece inspection - A company that has wide-open tolerances
that a setup person can easily measure (and be held accountable for) might
force the machines to remain idle while an inspector checks the first
workpiece.
Dimensioning and tolerancing - A company having many entry level
(lesser skilled) people may have design engineers that dimension and tolerance
on blueprints in a way that forces calculations to be done by everyone in the
CNC environment.
DNC system - A company having a great deal of repeated short-run
business (many program transfers) may have only a cumbersome distributive
numerical control system.
Again, inconsistencies that conflict with your corporate goals and company
profile will hurt you the most. Fortunately, most lead to serious bottlenecks
which can be easily identified. Unfortunately, they may be the most difficult
(and expensive) to eliminate.
Be consistent in your CNC practices
Though this may not always be possible (based upon the variety of machine
types you own), you can minimize confusion in the CNC environment by keeping
things as consistent as possible. Here are a few examples.
Machine and control types - Of course it is easier for everyone if
you can keep machines and controls the same throughout the shop. Unfortunately,
the technologies surrounding CNC are constantly changing, and machine tool
suppliers are constantly playing leap-frog when it comes to who has the best
features. To get the machine best suited to your needs may mean choosing a
machine/control combination that is unfamiliar to your people.
Programming methods - If programs are created in the same basic
format for each machine, anyone can look at the programs and understand
what’s going on. If you have more than one programmer, however, it is
likely that each is coming up with what they consider to be the best program
format. While each format will work, inconsistencies in programming will lead
to confusion among your people.
Operation methods - It is likely that you have more than one operator
running any given CNC machine tool. To avoid confusion and the potential for
mishap, each should be handling the machine in the same manner. Tool
maintenance - is one example of a potential inconsistency. If no special
consideration is given to when tool maintenance is performed, it’s likely
that tools will last a different amount of time for each operator.
