When the Premier Die Casting Company of Avenel, New Jersey started to machine large quantities of its casting, the choices of drilling and tapping spindles were numerous. They finally based their selection on service and technical support. Sotech Corporation of North Prairie, Wisconsin met Premier Die's requirements and is still their choice today for drilling and tapping units. The production ranges from drilling holes of 0.98-inch diameter at 7,000 rpm to roll form tapping of 1-12 threads, pressure tested for leaks.
Ed Zaremba of Premier Die Casting states, "The Sotech drill and tap equipment features simple, yet very effective controls which contribute to the high production uptime we experience on these machines. Also the multispindle heads have been reliable in our tough roll tapping operations."
The Sotech drilling unit's in-line design is said to be unique by the manufacturer because the force of the feed air (oil) is directly applied to the rotating spindle carrying the drill bit. A concentric mounted hydrocheck on the opposite side of the drill bit controls the feed rate. This concept is described as a very efficient use of air or oil as a feed force on a quill feed unit. All components in contact with shop air are either of non-corrosive materials or plated inside the drill feed cylinder. The leadscrew-tapping unit functions on the same design, with the screw-assembly on the same shaft as the tap. Therefore the tap entry can be precisely set for each tap size and a simple spring mechanism will trip a limit switch if the tap cannot enter the hole.
These features give Premier Die Casting the controls to make good parts, without relying on the operator to monitor for broken taps. Various special machines drill and tap large housings in stationary fixtures from as many as five sides. This also speaks for the compact size of the Sotech units with two mounting options on most models. "In addition we also drill tap, in one pass, with a Sotech two-spindle system that works just great," says Mr. Zaremba.
"The multispindle head MSBU type we use is fixed in center distance but can be changed with a different spindle plate. These heads offer us flexibility, interchangeable parts and are maintenance friendly. The machines we run here were built very cost efficient and have to meet a certain payback time," according to Mr. Zaremba. This was achieved with Sotech's assistance in selection, tooling and a performance guarantee.
Automation in drilling and tapping requires a reputable vendor, and standard operations include careful inspection for performance, fit and finish.
According to Mr. Zaremba, the partnership of a "supportive" vendor in machining automation such as Premier Die Casting's is imperative to be successful.
After several years of using Sotech units and components for machining our castings, they are still very satisfied, reports Mr. Zaremba.MMS