September 24, 2017

The good news is that removing the bar from the Toggle Mold Clamp did allow the clamp to apply pressure to the Game/Poker Chip mold at a lower, more optimal position. The bad news is that the backstop for the clamp is slightly taller than the mold, which keeps the injection nozzle from reaching the top of the mold. I cut some 1-1/2" x 36" x 1/8" aluminum bar stock into 5" strips to use as spacers. Although one spacer strip lifted the mold enough to make it taller than the backstop, the clamp was now applying pressure a little too high on the mold, allowing it to separate at the bottom under injection pressure. The addition of a second spacer strip was enough to put the mold where it needed to be.

I've posted pictures of the mold without spacers, the mold with spacers, the mold clamped in place, the clamp adjustments, and the injected Game/Poker Chips to Flickr.

One additional tip. The clamp head is mounted on a threaded rod, and can be adjusted with two nuts. This allows for the used of molds with different thicknesses. It also allows the tension of the clamp against the mold to be adjusted. I found it necessary to adjust these a couple of times, as they loosened with repeated injections. Will try some Loctite 242 next time.

Useful Link: Injection Molding Basics for the Minimal Mold (Seattle Robotics Society)

September 09, 2017

I removed the bar and side stop assembly from the Toggle Mold Clamp for the LNS Technologies Model 150A injection molding machine. The assembly is installed/removed using two top-mounted socket cap screws. The side stop assembly is further installed/removed using the single side-mounted screw. I've posted pictures of the bar and side stop assembly by itself and the Toggle Mold Clamp without the assembly to Flickr.

From time to time, I will post direct links to useful articles, videos, etc. Today's is a video on the plastic injection molding process in general.

Useful Link: Plastic Injection Molding (YouTube: engineerguy)

September 02, 2017

I replaced the original mold clamp included with the LNS Technologies Model 150A injection molding machine with their Toggle Mold Clamp. Installation is straightforward. The original mold clamp is held in place by four bolts inserted from the bottom of the baseplate. These four bolts are removed completely. The new clamp is held in place with two of the original bolts, which are inserted from the bottom of the baseplate through alternate holes already present. I've posted some pictures of the original clamp and the newly installed clamp to Flickr.

The original mold clamp works well, but the throat is too shallow for larger molds. I purchased their Game/Poker Chip Mold at the same time as the machine, and the original mold clamp would allow the top of the mold to separate slightly under injection pressure. The new clamp has a removable bar which is installed at the mold seating position with two socket head screws. When installed, the bar provides a higher seating position, placing smaller molds closer to the plastic injection nozzle. When uninstalled, the lower seating position allows pressure to be applied higher on larger molds. When I get a chance, I'll do some test shots and report the results.

Although not an issue for me yet, the Toggle Mold Clamp does offer a couple of other advantages. First, clamping pressure can be released/applied faster with a flip of the handle. Second, an adjustable side stop can be mounted to the previously discussed bar, allowing for faster repeated placement of the mold in the same horizontal position when the bar is installed.

August 30, 2017

I usually see the term "desktop manufacturing" limited to the various 3D printing methods. However, I am interested in a range of manufacturing methods for home/workshop use, including not just 3D printing, but injection molding, CNC machining, and pad printing as well. Unfortunately, information on these other techniques at a non-industrial scale in not necessarily easy to come by, especially in a centralized repository. I have been endeavoring to learn what I can about these methods as I go, and this site will serve as a way to store the information I gather for my own reference, as well as a way to share that information with others.

I have a number of other commitments. So, this site will not be updated when I have something new to share, more than on a specifically scheduled basis. For the time being, I am also forgoing much in the way of a graphical interface. Sooner or later, I’ll get around to dressing it up, but for now my interest is more in the content than the appearance.

I will be posting my thoughts on some of my personal equipment soon, including the LulzBot TAZ 5 3D printer and the LNS Technologies Model 150A injection molding machine.

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