J.P. seeing a pattern for fusion industry with the CTH, jumps on board to manage project.

From oil to solar power, the discussion of future energy sources is inevitable. One source that has yet to be utilized but may potentially be a limitless source of power is fusion. Thus, numerous institutions worldwide are investigating the effectiveness of fusion reactions.

These establishments have worked to construct machines that generate such reactions. But attempting to advance on a project alone would be too daunting a task for the engineers to handle. Outsourcing to other facilities has been a necessity.

Enter J.P. Pattern Inc. In 2003, the tool and die firm based in Butler, Wis., was commissioned by the Dept. of Physics at Auburn Univ., Auburn, Ala., for assistance in production of a Compact Toroidal Hybrid (CTH). The company would head the development of the machine's helical coil frame--a doughnut (toroidal)-shaped shell to keep in place the machine's helical coil, which helps contain high temperature plasma to cause fusion reactions.

Auburn asked J.P. Pattern to help create the pattern for the frame and also machine the cast component. In order to have single-source responsibility, the university additionally had J.P. Pattern subcontract to a metalcaster to cast the product. The company subsequently chose Eck Industries, Manitowoc, Wis.

Although J.P. Pattern has experience subcontracting smaller-scale components to metalcasting facilities, it had never overseen a project of such magnitude as the CTH. Thus, the challenge awaited as the company sought to tackle a proposal that demanded near total control of precise CAD revisions, proper casting techniques and impeccable machine work for such a unique industry.

J.P. Pattern was no novice to the fusion business. In 1994, the staff worked with the Univ. of Wisconsin Madison's Helically Symmetric Experiment (HSX) on CAD modeling, tooling and machining finished components.

"When Auburn released the contract, they had a minimal amount of people who we could involve with the project," said Gary Pull, co-owner of J.P. Pattern. "We were basically responsible for the entire project. It's easier to manage when you have less people to outsource to. A better timeline, too."

From the time Auburn sent the CAD model, J.P. Pattern and Eck Industries spent more than a year developing the frame. The CAD model was primarily designed by engineers at the Princeton Plasma Physics Laboratory (PPPL), Princeton, N.J. The finished shell component was designed as an assembly of 10 identical castings, with the shell's top and bottom made of five each. Hence, only one set of pattern equipment was needed. Once J.P. Pattern received the CAD models, adjustments had to be made, which was nothing unusual for the company.

"Probably 80% of the CAD models that we receive from customers need refinement," said John Puhl, president of J.P. Pattern. "we added draft (to the coil frame), locating features for our machining use and fillets and rounds to the CAD model. Reconstructive surgery is what I sometimes call it."

Creating the pattern was some what arduous for J.P. Pattern, as it deviated away from what the company was more accustomed to, such as those for automotive engines. Nevertheless, the CNC machined plastic and wood pattern equipment was sent to Eck for casting. However Eck's endeavor into the project was not without some conflicts.

"The casting was quite difficult," said David Weiss, vice president--sales and engineering at Eck. "The casting geometry was fairly difficult to put proper gating and risering where it was needed in order to make a good, sound casting. We went through at least two iterations, and the first couple castings were destructive testing parts."

Eck cast the 356 aluminum T-6 components (with an as-cast weight of 364 lbs.) in nobake molds and then sent the castings to J.P. Pattern for machining.

Using a 3-D contour machining process, J.P. Pattern worked to achieve the best precision, such as on adjoining surfaces and bolt holes. This too presented a challenge, as the machining was done with a 3-axis mill. This involved attaching a series of angle heads to the 3-axis machine that would normally be unable to reach particular areas on the casting.

"It was a little struggle for us to machine," said John Puhl. "We had to do some real tricks as far as fixturing, finding different angles for the cutter heads to mount to our machine."

J.P. Pattern persevered through this stage of production, and could machine areas of backdraft that otherwise would have required additional machine setups and fixturing to reach.

Once the castings were deemed complete, the company preassembled the shell to ensure all the pieces were in place. After a few more tweaks to the components for final inspection, the 10 castings were shipped to Auburn Univ. last spring, and assembled as part of the CTH machine.

As of now, Auburn is still in the construction stages of the CTH machine, but the helical coil shell is in place, measuring 8-ft. across. The machine is expected to be fully operational in early 2005. The university was grateful for J.P. Pattern's activity throughout production.

"We were very pleased with the product we got," explained Greg Hartwell, assistant research professor for Auburn's Dept. of Physics. "During the process of making modifications, they were really good at explaining why they wanted to do it. They made sure it was OK with us if they did it, and that it wouldn't cause any conflicts with what we had."

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Fusion reactions occur when hydrogen-like ions (attained from salt water) collide to form larger ions. Because particles of the same charge repel each other, they must be moving very fast. The ions are heated inside a confining electo-magnetic field, such as is produced by the helical coil in the Compact Toroidal Hybrid machine, forming a plasma. As the plasma temperature increases (surpassing 100 million degrees inside the field), the particles move more rapidly, increasing the chance for them to collide. Because the mass of the final ion is smaller than the colliding ions, the collision will produce a substantial amount of energy.