Chemical 'Machining' of Precise Parts


The photochemical machining process, also called photoetching, is effective for producing parts with complex geometries or with many holes where stamping, punching, laser or wire EDM might leave burrs and mechanical or thermal distortion.
Photo-etching fits in a spectrum of metal fabricating techniques that includes stamping, die blanking, punching, laser and water-jet cutting and wire EDM. Its particular advantages include the ability to process very thin materials, to 0.0005-in. thick; the ability to produce complex geometries, including fine meshes, screens and grids; the ability to hold dimensional tolerances to ±10 percent of the metal thickness; and the ability to quickly, and relatively inexpensively, produce quantities from a few to thousands. And, photo-etching does not impart any thermal stress or mechanical deformation in the metal.
The process uses inexpensive and rapidly produced tooling that can accommodate a family of part designs or multiple iterations of a design to accelerate the development process. Photo-etched parts can be produced from metal strips from 0.001-in. to 0.050-in. thick in as little as two or three days. Part sizes range from 0.100 in. with features as small as 0.004 in., to parts as large as 24 in. by 60 in.
> Tolerances and feature sizes
Locational tolerances of features produced by photo-etching are generally within 0.001 in. of drawing nominal. Dimensional tolerances in etching are a function of material thickness and of sheet size. The general rule-ofthumb is that the more generous the tolerances, the larger the sheet size and the lower the part cost.
The tightest tolerance range that can be achieved is ±10 percent of the material thickness for gauges smaller than 0.010 in. For gauges from 0.010 in. to 0.020 in., the range is ±0.0015 in. to ±0.0025 in. From 0.021 in. to 0.035 in., the most economical tolerance is ±0.005 in. Over 0.035 in., the dimensional tolerance band will approximate ± 20 percent of the material thickness.
The smallest hole or minor slot dimension must be at least 110 percent of the material thickness up to 0.020-in. thick, and 120 percent for metals over 0.020-in. thick. The thinnest land area between holes or slots must be at least equal to the material thickness. Minimum dimensions for both inside and outside radii are equal to the material thickness.
> Applications
Photo-etching is useful when time, tooling, part complexity, or material gauge are not well suited to more conventional processes. The process, convenient for “ganging” different parts on a single tool, is also helpful when there are multiple parts (of the same alloy and gauge) in development, or when there are a number of iterations of a design to be tested.
The ability to handle complex geometries or parts with lots of holes provides a distinct advantage over laser cutting, wire EDM, and even CNC punching, both in terms of cycle time and setup time. The ability to do partial-depth etching can eliminate subsequent coining or engraving operations, too. The etching process delivers clean parts and avoids problems of carbon, iron, or cutting lubricant contamination.

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WO-S students win precision machining state championship

April 13, 2009

West Orange- Stark High School Career Center students won the Texas State Championship, as well as third place honors, in the State Precision Machining Speed SkillsUSA competition held recently in Corpus Christi.

Fellow WO-S Career Center Student James Crabtree, also a senior, placed third in the same competition.

“I knew these two young men could do well; but to have two out of the three top places in the State of Texas is just overwhelming. It’s a feat that is hard to attain,” WO-S Career Center Precision Machining instructor Carlo Paulino said.

Kern and Crabtree say they both felt confidant with their individual performances in the four-part state precision machining contest. Competitors were required to produce an aluminum shaft on the lathe, an aluminum block on the milling machine, as well as take tests in layout and measurement. Each of the competitions included time limitations.

Also in the skills contests, dimensions are intentionally left off blueprints, forcing competitors to utilize math skills to problem solve.

“Just like they may find in industry,” Paulino said.

The lathe portion of the test was the part of the competition where the two WO-S Career Center students say they were able to pull ahead as only three of approximately a dozen state competitors finished their assigned projects, including Kern and Crabtree.

“We couldn’t predict who was first, second, or third,” Kern said.

Paulino said contest judges remarked that the competition was the closest that they have ever seen.

The lathe projects of each of the top three students in the state were only differentiated by 1/32nd of an inch apart.

Additionally, Kern’s state champion project was 1/32nd of an inch from being perfect, Paulino said.

The precision machining competition was held on a Friday, with the State Speed SkillsUSA awards program scheduled for the following afternoon.

Two hours into the awards, Kern and Crabtree were finally able to hear their results.

“I was relieved. You’ve got that cold sweat on your hands while you are waiting. When you hear your name, you just feel better,” Kern said.

Now he is focusing on preparing for Nationals by practicing and “sharpening up his rough edges.”

Paulino says the national test will require even more skill. National competitors will be expected to perform even more precise work, operate more and different machines, as well as complete a technical information and SkillsUSA knowledge test.

“It’s the best of the best. Only one percent of SkillsUSA students earn the right to attend national competition. It’s quite an honor. If you get that far, you can just about pick your job,” Paulino said.

Machine shop recruiters look at state champions, finalists, and the national competition as prime recruiting areas.

Kern said he does plan to use his precision machining skills during college. He is currently training to be a pilot and hopes to go into the United States Air Force.

Crabtree plans to use his precision machining skills as his career, utilizing his current skills to obtain employment, and then pursuing a precision machining apprenticeship.

With the first and third place finishes in the State of Texas, Paulino said that machine shops are already contacting the WO-S Career Center wanting to line up interviews with the two.

Both may be on their selected jobs before the end of this school year, he said.

The state honors the two have earned also gives them the advantage of entering the precision machining industry at wages above base pay.

WO-S Career Center also took home honors in job exhibit/project competition. Earning first place ribbons in precision machining were Kern, Crabtree, Lindsey Peoples, Dylan James, Robert Manning, Andrew Rogers, and Blake Thibodeaux.

Earning second place ribbons were D’Juantis Cotton, Jacoby Crawford, and Aaron LeBlanc.

Kern also won Best-of-Show honors in the job exhibit competition.

Along with Kern, James, Manning, Rogers, and Thibodeaux attend Bridge City High School.

In Auto Collision Repair job exhibit competition, Kory Freeman place third. Rick Brister in the WO-S Auto Collision Repair Instructor.

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Alexandria Extrusion Company Continues to Diversify
April 4, 2009

With considerations of the economy, competitors, customer needs, industry trends, and a great understanding of the financial health of the company, Alexandria Extrusion Company (AEC) continues to actively pursue and complete major steps to become process diversified. Aluminum extrusions are now just a part of the solutions provided by AEC.
Alexandria, MN March 24, 2009 -- Alexandria Extrusion Company (AEC) continues to actively pursue and complete major steps of its strategic goal to become process diversified, providing its customers with a variety of manufacturing processes through acquisitions and strategic alliances. AEC has aggressively developed and restructured its strategic plans for a decade or more. The end result is a progressive business model, with financial stability in a fluctuating economy and convenience for the end customer. Consideration of local and global economies, competitors, industry trends, as well as understanding the financial health of the company have played a critical role in the success of its strategic plan.
Doege Precision Machining - September 2008
Alexandria Extrusion Company's most recent acquisition was Doege Precision Machining, Inc (DPM). DPM is a leading manufacturer of precision machined, ferrous and non-ferrous components, located in Alexandria, MN. Since 1972 DPM has been committed to manage strategic growth by exceeding customer requirements and expectations within niche markets. DPM provides precision CNC milling, turning, cylindrical grinding, honing and assembly services, using a wide variety of ferrous and non-ferrous materials and shapes.
Services include full engineering and manufacturing support during new product development, including casting, forging and extrusion design. From design to prototypes through production, Doege Precision Machining is a true "partner" and a valuable resource..
M&M Metals - June 2008
AEC announced its acquisition of M&M Metals, a manufacturer of heat sinks and custom-fabricated aluminum extrusions, located in Carrollton, Texas. Since 1974 M&M Metals has been providing heat sinks including bonded fin and folded fin, custom-fabricated aluminum extrusions and machined prototypes. The company specializes in engineering support of thermal application designs, short run orders, timely deliveries and stocking of high volume production requirements.

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New E Mill Is One-Stop Solution For Machining Parts
March 25, 2009

Sterling Heights, MI - MAG Cincinnati's E Mill is a unique solution for economical machining of long, small cross-section parts used in aerospace, construction, shipbuilding and wind power. It is ideal for titanium, aluminum and composite work on stringers, spars, beams and similar parts. The E Mill performs contour machining, routing, drilling and tapping to produce finished, complex, 3D-geometry parts up to 12 m (39.4 ft) long in a single setup, reducing processing costs compared to vertical-platform machines. The innovative, economical design combines a production-proven 500 mm 3-axis horizontal machining center (HMC) with headstock and tailstock adapted from horizontal lathes to provide fourth and fifth axes of motion. The part manipulation system allows A-axis programmable rotation and 360° infinite positioning, while supplying V-axis linear travel for pull-through part feed. Work stock is loaded and unloaded from infeed and outfeed tubes.
The E Mill can be ordered with a choice of a 16,000 or 24,000 rpm HSK63A spindle. Supporting single setup processing, a drum-style automatic tool changer accommodates 12 tools up to 8 kg (17.6 lb) in weight, 200 mm (7.9 in) long, and 125 mm (4.9 in) diameter. The E Mill comes standard with full enclosure guarding, vacuum filtration and mist/dust extraction for CE and OSHA compliance - especially important for machining composite materials. A pressurized way system protects against wear from abrasive composite dust.
The headstock/tailstock system features through-hole chucks with powered jaws, allowing the work stock to be advanced incrementally through the jaws. The "live" headstock travels on V-axis linear slides, letting it move next to the stationary tailstock, lock on the workpiece, then slide back, pulling the work stock along. The system provides 1089 mm (42.9 in) of travel for incremental part indexing. The fully programmable feed system can accommodate work stock from 300 mm (12 in) to 12 m (39.4 ft) in length and up to 304.8 mm (12 in) square in cross section.
The headstock moves on parallel guideways 775 mm (30 in) apart, while the fixed tailstock offers a similar broad base. This gives excellent stability for coordinated A-axis part rotation.
Made from a tough industrial plastic, the infeed and out-feed tubes are clamshell designs. The in-feed opens from the top for loading work stock, with the outfeed bottom opening for ease of part removal. The tubes are seamless extrusions to prevent abrasion and delamination of composite materials, while the enclosed design provides additional containment of cutting fluids, part chips and dust.
The E Mill machine design can be adapted to larger machining centers with more powerful spindles for processing of harder materials. Besides cost savings over machining platforms with 12 m (39.4 ft) travel or more, the compact E Mill design saves valuable plant floor space, avoids fixture costs, and enables faster set-up for reduced WIP.

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Equipped with optical & multi-sensor coordinate measurement machine
Equipped with Mitutoyo Contour Measuring Instrument
Equipped with SV-210 vision measuring system
Equipped with STAR SR-20R3 CNC MACHINE
Equipped with STAR SR-20R2 CNC MACHINE
Expanding capacity by building a new factory
Equipped with STAR SR-20RJ CNC MACHINE
Equipped with STAR SR-20R3 CNC MACHINE

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