Manufacturing Page
Latch/Link Mold
The latch link mold consists of three link cavities and one latch cavity. Since several links and necessary to make a chain, having three of the link cavities on one mold is more efficient. The sprue runs down the middle of the mold, and the link cavities are laid on one side in such a way that the runners can enter near the center of the link, which results in more consistent molds. The latch cavity is located on the adjacent side, and the runner enters near the top of the longer side of the latch. Since the links and latch are symmetrical around their center axis, the parting line is also down their center axis.
The Latch/Link Mold
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Tumbler Mold
Since both sides of the tumbler are identical, the mold cavity is for one side of the tumbler. This mold was really easy to design as one of the sides is perfectly flat and thus one side of the cavity is simply a square. The other side of the mold is simply a negative of the inside of the tumbler. All necessary edges were given draft of 3 degrees to ensure removal from the injection molder.
The Tumbler Mold Cope
The Latch/Link Mold
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Mold Creation
The CAM process went smoothly, and there was no discrepancy between the design and the actual mold, except for one part of the tumbler. In our CAD part, the pin on the tumbler extends out so that it touches the other side of the tumbler. However, we actually realized after we made our parts that the pins were half as long as we had intended. After carefully reviewing our mold, we realized that the hole on the mold corresponding to the pin was too shallow, and thus there was most likely an error in the NC programming that cut off the pin too short. Other than this, the mold creation process went smoothly.
Mold Creation
The Molds
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Injection Molding
After carving out the gates for each part on the mold, we set the two mold cavities inside the injection molder. Although the TA had problems with the initial injections, the resulting parts were as we had expected.
The Injection Molding
The Injected Parts
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About Project
The plastic injection mold we chose to create was a lock and chain consisting of three main parts: the tumbler, latch, and links to form the chain. The locking mechanism uses the same principal as those found in common backpack clips
common backpack clips. The latch has flexible ends that deform around the pin on the tumbler and lock into place. The tumbler is composed of two identical square parts that have openings for the latch as well as a mating pin.
Team Info
- Jeff Butz
- Jeff is a senior in the Mechanical Engineering department. He is a member of both tau beta pi and pi tau sigma engineering honor societies and looks forward to working in industry upon graduation in June.
- Ned Cameron
- Ned is a senior in the Mechanical Engineering department. He has concentrated in MEMS, Nanotechnology, and Mechatronics while fulfilling the requirements for his degree. After graduation, he will work as Application Service Engineer for Informance International in Northbrook, IL.
- Sho Fujiwara
- Sho Fujiwara is a junior in Mechanical Engineering. He is concentrating in design, and hopes to either work in finance or engineering.