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Midwest Mold and Texture recommends polishing the mold surface to
ensure that the surface is free from flaws, smooth and uniform for
optimum texturing results. However, Makino has found that, by
utilizing specific milling processes, a high quality surface finish
can usually be achieved without polishing.
These findings were published in a Makino Die/Mold research report,
entitled "High Speed Milling on Quenched Steel " by Makoto Sato of
Makino. The report stated that, "by utilizing Flush Fine and `feed
equals pick' (f/P) processes advanced milling, the need for polishing
is nearly eliminated."
Flush Fine is a high speed, high definition and low heat machining
process pioneered by Makino. It combines high spindle speeds with
precisely controlled, high pressure coolant or forced air to blast
away chips and prevent heat buildup, either in the workpiece or the
tool. This permits high speed machining with greater thermal
stability and chip control, resulting in a superior accuracy and
finish, as well as high metal removal rate and longer tool life.
Taking surface finish to an even higher level of accuracy is the f/P
process, a ten year old concept verified by Makino testing. This
process adjusts feed rate equally to pick rate. When compared to
common machine milling, this process helps create highly accurate,
smooth, more uniform surfaces.
Under common cutting conditions, uneven, rough surfaces can be traced
to grooves created when the pick feed rate per revolution is smaller
than the pick feed creating grooves.
The f/P method eliminates this problem. "Surface roughness is the
smallest when feed equals pick for a constant machining efficiency
value," the report states. "Plus, the surface area that can be
machined by one tool increases when feed equals pick."
Used together, the flush fine and f/P processes allow die/molds to be
efficiently machined with a superior level of accuracy and quality.
This dramatically impacts several areas of the mold making process
which, in turn, reduces lead time and cost.
Nearly eliminate the need for polishing - When tested, a mold maker
verified that there is no visible difference between the embossed
surface where polishing was omitted and the embossed surface created
using the Flush Fine and f/P techniques. Manual adjusting and core
polishing of embossed surfaces are eliminated, allowing mold makers
to create molds in an eighth of the time.
Dramatically reduce machining time - The report documents a typical
mold process duration shrinking from one week to one half day long.
This is possible when flush fine and f/P cutting is used in the
machining process -- in the above example, the cutting time of four
tools was 3.2 times faster than conventional techniques.
Eliminate other processes - The above time savings is increased when
calculating time saved through process elimination. This means that
the mold maker can take a mold straight from milling to
texturing.
These benefits combine to create much higher production throughput
and a reduction in lead time, all while enhancing the texturing
process.
Located at the edge of the Clermont County Airport in Batavia Township, a suburb of Cincinnati, Ohio, Midwest Mold and Texture consists of two independent divisions. Combined activities of the Mold Division and the Texture Division involve building, modifying, repairing and texturing molds. The parent company of the Texture Division, Tanazawa Hakkosha, was established in the early 1900s, and is a pioneer and worldwide leader in the etching industry. Tanazawa Hakkosha is a developer of unique processes for producing textures.
