January 2007 Edition

Sawing

In-House Saws Put a Shop a Cut Above the Competition

Football may be a game of inches, but making a profit can be a game of eighth-inches. Cutting stock without waste keeps a suburban Chicago firm from sheering its net income.

American CNC is a respected machine shop managed by Joe Lanute, with his wife Mandy as company president. Founded in the early 1970s and located in a Chicago suburb, the company produces items for the medical instrument and agricultural machinery industries.

Setting the stop for accurate cuts without being “generous” reduces machining time when the pieces are moved to American CNC’s Haas machining centers

Along with precision-machined components, American CNC also fabricates radio-frequency – RF – isolation enclosures used around magnetic resonance imaging – MRI – scanners. American CNC has 40 employees in six buildings that include a quality control department where all of its products are inspected.

An integral factor in American CNC’s smooth-running process is a DoALL Model C-916A automatic band saw. Stock cut by the saw feeds 18 Haas machining centers. The saw cuts rectangles up to 9"×16" or rounds to 10-3/4". It can automatically index single lengths from 1/4" to 24" using powered vertical pinch rollers that feed the stock into the saw. Once the stock is loaded and the saw setup for the job, a cut counter monitors the number of pieces cut until a preset quantity is reached.

Cutting Classes

The saw is used for a 10-hour shift each day, cutting materials that range from plastic to aluminum to steel. Depending on the material, cuts take 30 seconds or more. Since parts machining may run more than seven minutes, the saw stays ahead of demand.

Saw setup is simple, so little time is lost when stock is changed. After loading the new stock, the operators adjust the manual work stop, speed and feed rates for the new stock, index length, and number of needed parts.

Lanute said the key to successful saw use is the operators. They are trained so problems such as inaccurate cut lengths, machine breakdowns, or extended setup times are eliminated. With automatic saw operation, the operator performs other tasks such as picking stock for the next job, cleaning the area around the saw, or delivering cut parts to a machining center.

American CNC uses its vertical saw to produce cut-away product models

“By cutting our own stock, we have a self-contained just-in-time delivery system,” Lanute said.

Service centers could pre-cut stock and deliver it at costs nearly the same as the cost for doing it in-house, according to Lanute, but vendor communications could fail when precision cut sizes are necessary and various materials are needed.

Too Much is Too Much

“When we worked with outside vendors we sometimes experienced what we called the ‘generosity factor’,” Lanute said. “At times, cut parts were delivered that were slightly larger than needed. They could even be as much as 1/8" too large.

“Getting more than we asked for may be good for some operations, but if the parts are too large for the machining centers, they have to be returned for re-sawing and that costs everyone time and money.”

A DoALL vertical contour bandsaw at American CNC is used both for miscellaneous jobs around the shop and an interesting specialty business: cut-away display models. The saw sections a product or component, such as gear housings, in half or pieces so they can be made into displays showing how the mechanism inside the housing works.

The vertical contour saw is a Model 2013-V with 20" throat distance from band-to-column and 13" maximum work height. It uses a 1" blade powered by a 2 hp AC motor with a variable 2-speed transmission. The first variable speed regimen is 55 to 300 fpm. The second is 960 to 5,200 fpm. Both speed domains are adjustable with the turn of a dial.

Another feature of the 2013-V useful for making cut-out displays is a 26"×26" table that tilts 45° right and 10° left to handle various materials, sizes, and shapes.

A third DoALL saw at American CNC is a Model C-916M used for general purpose sawing, primarily of structurals used in manufacturing frames for the RF enclosures in MRI rooms. RF enclosures insulate their contents from the radio frequency “noise” produced by an MRI.

The saw is similar to the automatic saw used by American CNC, but does not have automatic operation. An optional swivel vise permits miter cutting of angles up to 45°, useful in enclosure fabrication.

Vertical pinch rollers feed aluminum bar stock into the DoALL automatic, general-purpose band saw. Depending on the material, cuts take from 30 seconds to several minutes.

Keeping Mobile

American CNC added locking wheels on the saw base for easy movement. The wheels let workers move the saw around the shop. Moving the saw near the stock source side-steps stock double handling. The wheels let operators position the saw for angle cuts or when space availability makes it difficult to load long stock.

Lanute said the firm keeps its saws about for about 10 years, even though their useful life is longer. He said he estimates that after 10 years of hard use, it’s time to trade them in.

American CNC’s buy-American philosophy serves it well. With an American-made product, the company doesn’t have to worry about the availability of parts, importing through customs, or lost shipments. DoALL Sawing Products

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