Monday, January 2, 2012

Thermoforming Conversion Story: Concept to Reality - Tinker Toy Hub

Every now and then a project comes along that not only tests the broad capabilities of plastic thermoforming but also manages to be a lot of fun. Such a project came along when Techniform was approached by a client representing the Betty Brinn Children ‘s Museum to develop a large scale key component for their TinkerToy exhibit.

The required component was a scaled-up representation of the wooden hub used to interconnect the TinkerToy pieces, and fabricating the hubs out of wood was neither practical nor economical. It was determined that plastic vacuum forming was the only logical fabrication process for several key reasons.

Firstly, because the product needed to simulate a real wooden hub, a thermoformable wood grain laminate was used to achieve this appearance and this type of decorative laminate can only be formed using thermoforming since the laminate is applied directly to the plastic sheet during the sheet extrusion process. The sheet can then be vacuum formed with the stretchable decorative laminate pre-applied to the sheet. Secondly, since the production volume was relatively low the high tooling costs of other plastic forming processes were not feasible.

By choosing vacuum forming, Techniform was able to produce a low-cost epoxy mold to complete the production run and achieve the same high quality appearance on the outside of the part. Another advantage that Techniform brought to this project was its ability to produce tooling without any formal drawing or design by utilizing their in-house wood pattern shop. Although very few thermoformers still maintain pattern shops, Techniform recognizes the continued necessity for such a facility to better service certain types of projects that are better suited for “on the fly” development. Another trade technique used to keep the project tooling costs low was the use of “built-in-rout-guides” (known as BIRGS). This technique utilizes molded-in geometry along the trimmed edges and guides the cutting tool to trim the part from the scrap area. The hub’s structure consists of two vacuum formed pieces glued together which makes up one half of the hub, and then these two assemblies are bonded together as mirror image halves to form a complete hub. This type of design structure – the use of the same part in multiple locations - is yet another technique in vacuum forming utilized to keep the tooling costs low. Finally, the Tinker Toy Logo was hot stamp printed onto the hub producing a remarkably realistic large scale replica of the original wood hubs.


© 2011 Techniform Industries Michael Robinette


  1. Nice! This is a good addition to the many innovations on twin sheet thermoforming products.

  2. Thick gauge on the other hand, uses thicker plastic sheets that passes through a heating process and molded to its final formRotovac Group provide best product's related to thermoforming. for more infomation about Rotovac Group please visit:-