Case Study Book

INNO VA TIO N ENGINEERED

CLUTCH DRUM - COMPONENT CONSOLIDATION

Case Study

OVERVIEW

CUSTOMER

A Major OEM

CUSTOMER PROGRAM

Transmission

PRODUCT FAMILY

Clutch Drum

THE NEED

An OEM was preparing to equip its next-generation Heavy Duty pickup trucks with an all-new, high-torque 10-speed transmission.

OUTCOMES

Weight Reduction

Cost Reduction

Component Consolidation

 Tooling Reduction

Weld Elimination

Quality Improvements

INITIAL CUSTOMER APPROACH

The initial concept designed by an OEM was based on traditional technology, resulting in a two-piece assembly. One component was a stamped, splined outer shell, the other a machined hot forging. These two components were subsequently laser-welded together, followed by an induction hardening operation on the spine.

LIMITATIONS

There were several limitations associated with the original two-piece design.

Laser welding – although an established manufacturing process – is not typically associated with improving part quality. It can also create distortion in the finished assembly, requiring critical features to be machined or re-machined after welding.

The induction hardening process required on the spline of the machined hub also comes with potential quality concerns, as well as costs.

Finally, this design also required two suppliers, with the associated increased costs relating to supplier management, tooling and systems integration.

NETFORM SOLUTION

NETFORM, collaborating closely with the customer’s engineers, proposed an entirely new process that would have major benefits over the original design concept. NETFORM offered a one-piece solution as follows: A cold-formed preform blank (utilizing a process specifically developed for the this application) would subsequently be flowformed to manufacture the splined clutch drum as a one-piece. The benefits of this process are as follows: The cold forming process developed to manufacture the preform has major advantages. During the hub forming process on the preform, the hub undergoes significant work hardening, resulting in major strength increase in the material. This allowed for the elimination of the induction hardening process, along with its costs and product quality concerns. An additional benefit gained by cold forming the preform is design flexibility. Firstly – the cold forming process allowed variation in cross sectional thickness. This allowed the engineers at the OEM to combine the two parts into one, eliminating the laser weld. Secondly, a sharp radius between the hub and the back face – that was not possible with the original stamped component – became possible with the cold forming process.

The part went into production with the envisioned improvements and cost savings were achieved. The induction hardening and laser welding processes were eliminated. The component passed all product development testing without issue and has been in production without a single quality issue for over Three years.

This case study is an example of the NETFORM non-traditional approach to sales. Customer prints are starting points only, engineers are engaged to fully understand needs and requirements, and NETFORM-generated ideas submitted to the customer for consideration.

SPLINED HUB – COST REDUCTION

Case Study

OVERVIEW

CUSTOMER

A Major OEM

CUSTOMER PROGRAM

4F27E Transmission

PRODUCT FAMILY

Splined Hub

THE NEED

An OEM needed a splined hub component for an automatic transmission application.

OUTCOMES

Cost Reduction

Component Consolidation

 Tooling Cost Reduction

Quality Improvements

INITIAL CUSTOMER APPROACH

An OEM created a process that involved tubes imported from Japan that required a rotary necking and spline rolling operation.

LIMITATIONS

The existing process utilizes tubes that undergo a rotary forming process to make a splined hub. These tubes have to be imported from Japan to meet significant formability requirements. In addition, the rotary process is not a fast process. Once the tubes are necked down to a certain profile, they are then put through an additional process for rolling in the splined teeth.

During the development of this component, the OEM discovered the cycle time was nearly twice that originally planned. This led to the OEM having to buy an additional machine (instead of the planned single machine). This led to higher capital expenditure, increased perishable tooling costs, and increased labor costs.

NETFORM SOLUTION

NETFORM met with the transmission plant and reviewed the component and process in detail.

NETFORM came back with an alternate proposal. The new concept utilizes a flat blank hit in a press, cold-forming both the hub and the spline at the same time. This process produced teeth with the same profile as the original rolled design, but with the added benefit of work hardening. The new component would drop into the existing machining line, have improved dimensional quality and, most importantly, be a cost savings to the OEM.

The component was developed and tested from a product performance point of view, before samples were evaluated by the manufacturing department at the OEM. All the testing went well, and the component was introduced into production and launched without issue. This component is a perfect example of how NETFORM can redesign a component for cost saving.

PLANETARY CARRIER – COMPONENT CONSOLIDATION

Case Study

OVERVIEW

CUSTOMER

A Major N.A. OEM

CUSTOMER PROGRAM

9 Speed Transmission

PRODUCT FAMILY

Carrier Shell and Pinion Carrier

THE NEED

The OEM was developing a nine-speed transmission and had a complex assembly for transmitting torque in the planetary carrier area.

OUTCOMES

Weight Reduction

Cost Reduction

Component Consolidation

 Tooling Cost Reduction

INITIAL CUSTOMER APPROACH

This assembly comprised of three components a flowformed outer shell, a powdered metal carrier, and a snap ring that kept the two components together

LIMITATIONS

The initial design, required three components, three suppliers, and three sets of tooling. A large amount of the material from the largest component was removed during the manufacturing process. An additional powder metal component took the place of this removed material and required a complex snap ring assembly process.

NETFORM SOLUTION

Instead of quoting the existing design NETFORM came back with a proposal with multiple benefits. This new concept would utilize a lightweight, cold formed carrier in place of the heavy complex powder metal carrier from the original design. The cold formed carriers would be pressed into mating slots in the back face of the flowform shell and then laser welded into place. Replacing the powder metal carrier and snap ring with a laser welded cold formed carrier solved the problem of the loose joint and improved the alignment of the components. These design improvements allowed for major weight savings, reduced machining, and cost savings of $2 per assembly.

This concept was prototyped and passed all testing. The assembly went into production and became the design standard for this assembly in subsequent transmissions.

SPLINED HUB – QUALITY ISSUE SOLVED

Case Study

OVERVIEW

CUSTOMER

A Major OEM

CUSTOMER PROGRAM

68RFE

PRODUCT FAMILY

Splined Hub

THE NEED

A major OEM had a need for a splined hub to drive clutch plates in an automatic transmission.

OUTCOMES

Cost Reduction

Component Consolidation

 Tooling Cost Reduction

Quality Improvements

INITIAL CUSTOMER APPROACH

The hub entered production as a two-piece assembly. This assembly comprised of a stamping that featured the clutch plate splines, a machined hub and a subsequent assembly operation/laser weld. The machined hub incorporated spline features and various other key dimensions that were fully finished prior to laser welding.

LIMITATIONS

The main issue with the two-piece design was part deformation during the laser welding process. The finish machined hub, when subjected to the heat from the laser welding process, distorted in relation to the stamping.

The correction required for this two–piece assemblymachining critical dimensions in the hub after welding –was not possible due to equipment requirements and supplier

NETFORM SOLUTION

NETFORM reviewed the issues with the engineers at the OEM and proposed a new process. In this new process, the hub and the splined stamping were combined into one component. This concept – impossible with the original stamping process due to the varying cross-sectional thicknesses – became feasible with the utilization of the cold forming process. This eliminated the need for the laser weld, eliminating i) scrap due to weld quality issues and ii) distortion of the hub due to the laser weld heat. NETFORM developed the ability to cold form the splines during the main cold-forming process. This is done in the forming hit with tooling that cost a fraction of the multi-station stamping dies.

The consolidation from two parts to one and the quality improvements resulted in a $2 per component savings. NETFORM eventually took over the full production requirements without any quality issues. This concept was prototyped and passed all testing.