Unusual shapes - Just business as usual for Northfield

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Mascotech Sintered Components

Mascotech Sintered Components are the second largest powdered metal automotive parts maker in the world, and a valued Northfield Customer.

Sintering is not a new technology, but it can provide tremendous financial savings in parts processing.

  1. The process starts with metals in powdered forms. Several alloys are combined to create a new material with specific properties.
  2. Powdered metals are put into a mold then compressed, under several hundred tons of pressure, causing them to fuse.
  3. Finally, the piece is released from the mold, this is called the green state, put into an oven, and sintered.

The result is a strong, economically produced, near complete component.

In addition to doing the powdered metal work, Mascotech also performs roughing and finish machining on some of their parts. This is where Northfield comes in, supplying three unique custom solutions.

 

Transfer Case Component

For this automotive transmission component, Mascotech needs to finish the bore and cut two grooves. These hold a snap-ring and a wave spring.

The Challenge

Cutting the grooves with a forming tool develops up to 20 horsepower, meaning the part needs to be held very securely while the material is removed. However, the part has thin walls, making it difficult to grip without deforming it. Since all the machining operations will take place at the same time, maintaining roundness is critical.

Solution

We solved the problem by outfitting our standard 8″ Model 800 3-jaw chuck with custom full circle jaws that locate and grip the circumference of the part with a drive pin to pick up most of the torque.

 

Water Pump Component

Like many powdered metal parts, this water pump component comes out of sintering nearly complete, but still requires a final operation. In this case:  machining the bore, flange cutting the treads and tapping the holes.

To hold this part, Northfield provided one of our standard Model 670 2-jaw chucks fitted with custom jaws to grip the outside diameter of the part. Special orientation pins help locate the part for finish machining.

 

Crankshaft Sprocket

The final project is creating a family of sprocket gears. After sintering, the material has a particle hardness of 58/63 Rockwell “c” scale. Mascotech needed to hard turn the bore.

Challenge

The main challenge is the keyway between the gear teeth.  It makes one section of the work piece very thin and introduces an interrupted cut during machining of the bore.

Solution

Our solution employs a 4″ diaphragm chuck with six jaws to grip the major diameter of the gear teeth and three pads for axial banking. One of the jaws has a drive pin to insure no slippage while holding the part very gently.

Using our chuck, Mascotech is able to achieve a roundness specification of less than 0.0002 inch when machining the bore. Mascotech utilities Northfield work holding for over 80% of their turning applications at their Ridgway, PA facility.

Northfield Precision Instrument Corp.: Northfield is a custom work holding solutions company based in Island Park, New York.

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