Category: Automotive

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Custom Automotive Diaphragm Chuck - Plastic Top Tooling

Northfield 3-jaw, 5” Diaphragm Chuck (DPH-500) with custom plastic top tooling
Northfield 3-jaw, 5” Diaphragm Chuck (DPH-500) with custom plastic top tooling

Customer Brief

Our customer is a heavy duty fuel pump and injector systems manufacturer. They requested a method to accurately grip their small (.098” OD) fuel injector plungers without marking them.

Challenge

Chuck close up, with part and custom stop.

The tip of their part must rest in a carbide seat, ground central to the chuck. This requires the special part stop.

Northfield Solution

Northfield 3-jaw, 5” Diaphragm Chuck (DPH-500) with custom plastic top tooling, disassembled view with part.

The jaws are made from a special, highly abrasion-resistant, engineered plastic. Designed to withstand repeated clamping with minimum wear. The bore diameter gripping the part yields an accuracy and repeatability of more than 50millionths” TIR total runout to the chuck’s center line.

Do you have a similar part? Then get in touch and see how we can help.

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Unusual shapes - Just business as usual for Northfield

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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Northfield Chucks Help Dana Corp Stay On The Road To Success

Dana Corporation

Manufactures drive shaft components for the big three auto makers. At Northfield, we’re proud of the part we play in helping them solve their production challenges.

8000rpm_Diaphragm_Chuck

 

Challenge – Getting a grip on the situation

Dana needed a chuck to be mounted on a balancing machine holding a drive shaft on one end, gripping the component called a slip yoke. These drive shafts, for the Daimler Chrysler Corporation, were complicated by several factors.

  1. The shape of the part – long and thin –
  2. The grip force required to hold a 5ft. long drive shaft
  3. The accuracy 1/10,000 T.I.R.
  4. The speed – as high as 8,000 rpm – during the balancing process.

Normally, balancing operations are performed at only 900 rpm, but Dana needs to balance this part at simulated road conditions. Since the shaft will deflect (bend) at high speeds, this is the state they want it balanced at. For production cars, drive shafts typically rotate up to 3,000 to 5,500 rpm. This component, used in Daimler Chrysler’s high-performance stock racing cars hit 200 mph with their drive shafts rotating at 8,000 rpm.

Solution – Sometimes, two chucks are better than one.

To solve the problem, Northfield engineers decided to use a diaphragm chuck, rather than a sliding jaw chuck. Before making the final decision we conducted several tests using solid models on our CAD systems. This ensured that our diaphragm chuck wouldn’t lose grip force at these high rpms.

Our solution consists of two separate diaphragm chucks, with two separate sets of jaws, mounted one in front of the other. This  accommodates the long, thin shape of the part. With one set of jaws gripping near the front of the piece and the other gripping near the rear.

Results

The result is accuracy of a 1/10,000 T.I.R. and repeatability to 50 millionths of an inch and extreme rigidity.

The chuck also uses a male spline driver mounted in the center of the chuck. This helps drive the shaft on start up and stop, and guide the shaft into the jaws during loading. These drivers are .002in. undersize of the internal spline and must not influence the centering of jaws. The spline driver is a gauge quality piece of tooling supplied by Michigan Spline Gauge Co.. Providing a concentricity of less than 50 millionths with the chuck.

In Dana’s production car area, the chuck runs the same component. In the stock car application it is used to run a several different components. Parts and tooling can be switched and still maintain an accuracy of less than a 1/10,000 T.I.R.

Finally…

This chuck was designed to be air opened with a self-contained clamping system to meet Dana’s safety standards. It uses the spring pressure of the diaphragms for clamping that will hold the part in place if air pressure and power are lost during the balancing operation.