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Prototyping a Little Differently

Jan. 29, 2014
Drawing on experience Tooling, complex parts Core gluing fixtures UNItube system

Humtown Products took its first plunge into additive manufacturing in April 2013, working with a simple desktop 3D printer capable of printing PLA plastic.

The printer sparked interest throughout the company and over a short period of a few months, multiple uses of the 3D printer were found. Humtown expanding upon plastic printing in May 2013, converting from the typically lengthy production of foundry tooling using CNC machines and conventional patternmaking skills to skipping the step entirely — going straight for 3D printing sand molds and cores using ExOne sand printers and having a local foundry pour the castings.

3D-printed drag mold.

Humtown was able to draw on extensive experience and understanding in patternmaking methods, as well as knowledge in CAD design, to design molds that fit right into typical foundry methods but didn’t require the typical foundry tooling. What makes this development even better is that not only did the additive manufacturing of molds and cores help the company reduce lead times for building typical tooling for the project, it also cut down on costs.

Since then, Humtown has completed multiple projects for 3D-printed molds and cores, and continues to pioneer this new age in metalcasting process technology. To show its commitment, Humtown joined its newfound capabilities in additive manufacturing with its established capabilities in CNC machining, and in August of 2013 it formed an Advanced Manufacturing Department.

3D printed cope mold.

This new department focuses on providing customers cost-effective tooling or solutions to make sure that they are making the casting or part economically, and with the shortest-possible lead-time. The department has already generated exceptional products, such as loose pieces that were reverse engineered from existing and worn pieces. The new loose pieces were designed in CAD and printed on the 3D printer to check fit. Once the new loose pieces fit, the patterns were printed in stainless steel, and now will hold up to thousands of uses in the old tooling. Due to the complexity and size of the loose pieces, they were actually printed at lower cost than they could have been machined out of the same material.

Humtown has also seen the benefits from 3D printing of plastic for core gluing fixtures. Using Humtowns’ FARO arm 3D measuring device, measurements of an existing pattern were taken to create a core gluing fixture that holds the cores in place for assembly and gluing. The fixtures were printed out of complex shapes that made it simple for the core finishers, and could not have been manufactured for the same cost by the conventional method.

Ultimate Blow Tube System

Another product of Humtown’s expertise is the UNItube system, an answer to many problems commonly encountered in production coremaking. Misalignment of the core machine at the squeeze-blow position can damage an “unyielding” metal tube or the core box. The UNItube absorbs greater misalignment stress due to its high-impact plastic design. Metal blow tubes, with their rigid construction and inflexibility literally chew up your profits due to damaged core boxes caused by misaligned blow tubes.

Since Metal blow tubes are manufactured in fixed increments of length and diameter, a core shop must stock many sizes of tubes and tips for service replacement. But by simply trimming the UNItubes’ tip with a sharp knife, you can custom-design the tube to suit whatever requirements you have. The UNItube is easy to install, simple to replace, and adjusts to any size simply by cutting the end to achieve the desired rate of flow.

The UNItube System seats into a single angle cone, steep enough to minimize sand retention. The blow plate requires only one 30-2 mm tapped hole – a substantial savings over conventional metal blow plate preparation. The 30-2 mm tap and the special cutter for forming the socket are available from Humtown.

Humtown Products also provides the UNIplug, a tube with a thicker wall that allows the installation of a core vent for use as a gassing or tamping tube.

Core gluing fixture.

Humtown Products is committed to providing our customers with high-quality products and to establishing a lasting working relationship that is always responsive to your manufacturing needs.

We constantly strive to improve and update our manufacturing technology. Whether yours is a high-volume or low-volume production foundry, Humtown Products can serve you quickly and efficiently - and help you operate more cost effectively.

Humtown has gained expertise since its first additive manufacturing projects. Visit for more info.