Die caster lets inventor Twist again

Materials advice helps inventor bring method for controlling moisture and pest infestation to market.

Few things can splash more cold water on the starry-eyed dreams of inventors quicker than the realities of developing and bringing a product to market.

A good business plan is key, but even more important is knowledge of the industry and the expert advice of trusted suppliers.

Fortunately, George Allen of Inject Solutions had all three.

After many years in construction, replacing rotted and insect-damaged sills and framing, Allen thought there ought to be a better way for homeowners to protect against the ravages of pests and moisture.

And when a long recuperation from hip replacement surgery gave him the time to work on it, he found the answer.

His Twist thermal wall injection system and treatment uses permanently installed injector plugs that allow the direct infusion of pesticides, wood preservatives and other chemical treatments inside wall and ceiling spaces where problems occur.

After treatment, a plastic cap covers the plugs, making them very unobtrusive and allowing easy access for future treatments.

Marketed to homeowners and pest control professionals, it claims to be the first safe and effective way to deal with pest and moisture problems directly, and has already garnered positive attention in the pest control press.

But, as every successful inventor knows, taking such a product from concept to reality can be a daunting and costly undertaking.

For Allen, this process was greatly facilitated - and many thousands of dollars were saved - by the advice and assistance of die caster Fielding Manufacturing.

"Allen's original design called for the injector plugs for his Twist system to be cast from aluminium", said Steve Fielding, President of Fielding Manufacturing.

"But when he also said he expected to produce rather high volumes, I suggested zinc might be the better choice".

Aluminium casts at a temperature above the tempering point of die steel, Fielding explained, while that of zinc is lower.

"Every shot with aluminium works to anneal the tool", he said, "and after 100,000 to 150,000 units, you have to rebuild or replace the tool".

"Zinc die-cast tools are good for millions of parts".

But it was in product development that Fielding's expertise provided the most critical savings for start-up Inject Solutions.

"My original design called for delivery slots at the inner end of the plugs to be spaced at 90 degree intervals", said Allen.

"Fielding pointed out that thousands of dollars could be saved in tooling by making these slots closer together, and that rather than build the tool right away, we should test the design with rapid prototyping".

As the plug geometry was rather straightforward, Fielding was able to machine prototype plugs from con-cast zinc bar stock which provides up to 85% of the strength of an actual die-cast part.

This allowed actual in-use testing which validated the redesigned slot pattern.

"In fact", said Allen, "we actually get better coverage of interior bay surfaces with the offset slots than we did before".

Prototype testing also highlighted the need for a number of other design changes, two of which had significant impact on the final product.

The Twist system uses two types of injector plugs, a self-tapping one for exterior wall installation, and a machine-threaded version with an anchoring mechanism for interior wallboard installation.

The original design called for a metal toggle-bolt anchoring system, but Fielding suggested that a plastic, molly assembly would be less costly to produce and would also facilitate installation.

And as Fielding is also an injection moulder, the assemblies could be produced in tandem with the injector plugs.

The final design alteration involved the cap for the system.

"Allen was looking for an off-the-shelf cap he could adapt for his purpose", said Fielding.

"We suggested that a custom moulded cap would not only function better, but would also enable him to brand his product".

"We added two mating indents onto the plug flange and designed a quarter-turn, twist-on cap that has his web site - www.injectsolutions.com - embossed on its face".

"The mating indents also had an unexpected benefit for installation of the final product by providing an orienting feature to position the dispersion slots for maximum coverage".

Allen said: "The whole system is designed to be installed with a 2.5cm drill and a 1.25cm socket or extension".

"In fact, the plastic molly design on the interior plugs works so well, you can snug them up using a 1.25cm ratchet extension like a screw driver".

The prototyping and testing process not only proved the original product concept, but resulted in a production part that improved upon the concept, was more economical to produce, and provided a branding mechanism that was not even imagined in the original.

"Fielding has helped me tremendously", said Allen.

"And I've got a better product as a result".

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