Coated Tools Can Provide Double Output With Same Tool
The F. P. Schmidt Manufacturing Company makes accurately machined parts in high volume, directly from coiled wire stock, on automatic and semi-automatic machines of its own design and construction. These machines knurl, thread-roll, mill, swage, press and cut a variety of materials such as brass, aluminum, carbon steel, 52100 roller bearing steel, and types 303 and 416 stainless steel. Schmidt's products usually form part of everyday consumer items, such as appliances, toys, hand and power tools, plumbing and electrical supplies, office equipment and automobiles.
Each part the company manufactures has its own precision form tool profiled in the shape of the cut, and is made of either T5 or M4 tool steel. Because coated tools are claimed to exhibit high-surface hardness, resist corrosion, and have low coefficients of friction, F. P. Schmidt began researching and sampling various coatings, hoping to reduce their production costs. Based on their findings, they selected Titankote-C, manufactured by Richter Precision, Inc., 1021 Commercial Ave., East Petersburg, PA. This coating is a physical vapor deposition (PVD) titanium nitride (TiN) coating at thickness of 0.0001-inch on each side of the tool.
PVD coatings, such as Titankote-C, are produced in a vacuum chamber at low temperatures as low as 650[degrees] F. In the vacuum chamber, TiN ions are transported by physical means, although they may be "directed" by polarizing the tool surface. The force of the TiN ions bonds the coating to the metal surface Although tools can be coated before or after sharpening, Schmidt decided to coat their tools before sharpening. In practice, and coating covers the side of the tool that wears most, while the front rake remains uncoated. These particular tools have between a 15-degree to 25-degree rake angle, depending on the material and the finish the customer requires.
F.P. Schmidt found that coating not only improves their own form tools, but those in a secondary operation, such as milling cutters, as well. One product operation requires milling the punches for paper punches. These steel punches are cut to form and shape on automtic machines. A V-shaped groove is milled in the one end that is to punch the paper. The punch is then heat treated. Finally, the finished cutting edge is ground in a centerless grinding operation.
The company says that after coating their tools, they notice an increase in tool life. Tools that previously turned out 200,000 workpieces now turned out 500,000 to 600,000 workpieces. In addition, this increase in the number of workpieces includes a variety of materials ranging from aluminum and brass right up to 52100 roller bearing and 303 and 416 stainless steels.
The company feels that utilizing a coated tool coating is relatively inexpensive when compared to the cost of a new tool, even if there is only a marginal increase in tool life. If a coated tool lasts longer than an actual second tool, then any use of the tool after that is all savings. Increased production per minute and better finish, at a lower cost, are the reasons F. P. Schmidt has been coating their tools for four years.
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