The Old School Side of Injection Mold Making

Back in the olden days of mold making, there werethe past, and the simplicity and efficiency are a marvel
obviously no CNC machines and no CAD/CAMto behold.
programs. Can you imagine that! Just consider, if youIt is the same with complicated setups on the
have the background to do so, how much is done onBridgeport manual milling machine. In the not-to-distant
the CNC EDM's, WEDM's, vertical machining centers, 5past, the majority of work was done on these
axis machines, and more. That would be just aboutmachines. Now they are just handy machines for
everything.simple tasks like EDM blanks or WEDM blocks.
Then, consider how much work is done in the designOccasionally there is a repair or engineering change
area by the computers and the mold design software!done manually, but even that is a rare occurrence.
I cannot even remember the last time I sawWhich mold maker is not thankful for the incredible
somebody using a drafting table.speed, precision and ability of the CNC machining
One thing that always amazes me is how every singlecenters or EDM's? The tedious tasks and nerve
mold has to be hand finished. While it is true that somewracking jobs are mostly gone, now we have
molds do not require much hand work, they all do, todifferent problems to deal with.
some degree. If you consider the surface grinding, moldAnother big change is in the mold polishing area. With
polishing and hand fitting, there is actually a lot of finishthe ever-increasing abilities of the EDM machines and
work done manually.high speed milling machines to leave a fine finish, much
Often you can hear salesmen and engineers givingof the need for manual polishing is gone. Hallelujah! The
tours to prospective customers. At times it borders onendless blending of mismatched surfaces and rough
the comical; some of the comments are so far off.finishes with deep cutter marks is thankfully gone.
My favorite is when one told the tour group that weNow, the polishing is more focused on diamond finishes
inserted raw steel into a Haas machining center, ran itand textures. This has become much easier because
through a Makino high speed mill, then a Sodick EDM,the finish is already usually quite good from the
and voila! There was the finished mold! The customermachining operations.
just nodded his head as they shuffled along the aisle.So, with the changes in the milling machine, surface
Several of us were literally holding back the laughtergrinder and mold polishing, what is left? Good question!
with our hands over our mouths.Now the problems are just as difficult, it is just that
In reality, the modern mold making shop is athey have changed.
combination of the new and the old. The days ofSome of the newer problems are the complexity of
complex setups on the compound sine plate tomolds, very short lead times, global competition, and an
surface grind a precision angular shut-off are mostlyacute shortage of the old school mold makers. There
long gone. This is due to the wonderful ability of themay be less of a demand for this old skill, but the
WEDM machine. The accuracy is just as good as insupply is quickly disappearing.