Advantages of Vertical Molding Machines vs Horizontal Molding Machines

While horizontal molding machines were the first of their kind to become a standard in plastic manufacturing, vertical molding machines may be a more sustainable way of molding for certain applications and many manufacturers are now to utilize their many advantages. With the advancement of injection molding becoming more standard in consumer products, it's time to delve deep into the differences of its sub-groups.

This article will map out the difference between vertical and horizontal molding machines and will mention the advantages of vertical injection molding.

If you were to visit the American Injection Molding Institute, you would see a variety of molding machines. But only by working on the machines would you be able to know exactly what works best for you.

Vertical molding machines are more flexible in terms of efficient production cycles, cost, and types of products it can handle. Take insert molding as an example. This is when a pre-formed product is inserted into a mold that needs plastic formed around it (see pictures).

Each cycle requires having the finished product taken out of the mold, and a new one added before the molding process begins.

Attempting to do this on a horizontal machine would be difficult and awkward as you would be fighting gravity, slowing down production and raising the risk of bad parts. Horizontal molding creates even greater risks when it comes to medical injection molding, which requires high tolerance parts.

With a vertical molding machine, the parts can easily be placed in the mold quickly and comfortably without having to worry about the insert becoming misaligned.

Learn about injection molding basics and how injection molding works here.

An added advantage to vertical molding machines is pairing book molds with a rotary table.

Book molds close on the inserts and hold the pieces tightly in place before, during, and after the molding process. Rotary tables can hold between 1-12 molds at a time and rotate giving the mold technician to time to replace the insert without holding up the molding process.

Multiple book molds on a rotary table can offer the fastest cycles and highest possible yields in molding. They also allow different molds for a family of products to be run at one time.

The video at the top of this article shows an example of a vertical injection molding machine with rotary table.

Another advantage of vertical injection moulding machine vs horizontal is that they take up well over half the space required for a horizontal molding machine. See the two machines pictured side-by-side:

Additionally, the vertical clamp units on vertical molding machines are versatile and allow maximum flexibility with associated mold tooling.

Vertical injections can offer more control when the resin reaches the mold cavity through a short distance. Often times with horizontal machines, the plastic has to travel a longer distance to reach the mold which makes room for resin to cool too quickly and produce bad shots.

Two huge factors that play a major role in the quality of a product formed by vertical insert molding are clamping force and shot size.

Clamping force is the amount of pressure required to keep the mold and product closed during the injection process. On vertical machines, especially when using book molds, the clamp is more of an added precaution since the top of the mold will be kept in place by gravity.

Additionally, the vertical clamp units on vertical molding machines are robust and allow maximum flexibility with associated mold tooling.

Shot size is the amount of molten plastic required in the injection process of the mold. Since the plastic is coming from the top, the size of the runner needed to complete a part is much less than that of a horizontal molding machine. This helps cut costs and reduce waste while keeping the process as efficient as possible.

What did we miss? Tell us below what you think are the main differences between vertical and horizontal molding machines.

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