Injection Molding Machine

Plastic injection moulding is a large industry that generates a high amount of revenue each year. With the constant demand for plastic products from different companies, it is the goal of the industry to be able to produce and deliver them on time. Plastic injection moulding machines allow you to create so many products that are high quality in a short period of time.

When it comes to the plastic injection molding machine itself, it is an efficient machine that would be able to handle the stress and rigors of manufacturing. It is best to make sure that you have the best machine for the job, as not only you would need to produce, but also make sure that products are of quality, and is safe to handle. Here is a short beginner’s guide on how to pick the right plastic Injection Molding Machine.

What Are Some of The Considerations For Injection Moulding?

Before you endeavour to produce a part via injection molding considers a few of the following things:

1. Financial Considerations

1.1 Entry Cost:
      Preparing a product for injection moulded manufacturing requires a large initial investment. Make sure you understand this crucial point up front.

1.2 Production Quantity

      a. Determine the number of parts produced at which injection moulding becomes the most cost effective method of manufacturing

      b. Determine the number of parts produced at which you expect to break even on your investment (consider the costs of design, testing, production, assembly, marketing, and distribution as well as the expected price point for sales). Build in a conservative margin.

2. Design Considerations

      a. Part Design: You want to design the part from day one with injection moulding in mind. Simplifying geometry and minimizing the number of parts early on will pay dividends down the road.

      b. Tool Design: Make sure to design the mold tool to prevent defects during production. Consider gate locations and run simulations using mold flow software like Solid works Plastics.

3. Production Considerations

      a. Cycle Time: Minimize cycle time in as much as it is possible. Using machines with hot runner technology will help as will well-thought-out tooling. Small changes can make a big difference and cutting a few seconds from your cycle time can translate into big savings when you’re producing millions of parts.

      b. Assembly: Design your part to minimize assembly. Much of the reason injection molding is done in southeast Asia is the cost of assembling simple parts during an injection molding run. To the extent that you can design assembly out of the process you will save significant money on the cost of labour.

4. Decide what kind of plastic you would use

In the plastic injection molding industry, different kinds of plastic are being used to craft certain products. If you are planning to use a wide variety of plastics for your products, get a machine that would be able to handle it with ease. Not all machines are created equal, which means there might be some machines that would have a difficult time producing certain kinds of plastic. Versatility is the key in the plastic industry, which is why you should take it in as another deciding factor.

5. Pick the machine type

Plastic injection molding machines have three distinct designs, namely fully electric, fully hydraulic, and Hybrid. These machines run on pumps, and choosing between hydraulic and electric plays a factor on how you should do maintenance on it, along with how well it would perform. This would also help you look for the right kinds of parts to use in case that you would have to repair it.

6. Pick the right size

Plastic injection molding machines come in different sizes, which mean the bigger machines would be able to create larger products. Size is also a factor when it comes to machine maintenance, as larger machines would need more care and regular checks to keep them running well. Size is also a factor in production cost, as smaller machines might be able to consume less electricity, while using a bigger machine would significantly need more power.

While selecting injection moulding machine the following specifications are required to be evaluated.

Key Takeaway

Injection molding machines are some of the most versatile machines around, and being able to choose the right one for your company would mean getting a good amount of profit. By looking into these factors, you will be able to find the right machine that would work for you.

How to choose an injection molding machine?

1. Injection Weight

Injection weight is an important parameter of the injection molding machine. It is the most commonly used parameter when choosing an injection molding machine, expressed in ounces or grams. Although this parameter is simple and easy to understand, it is also easily misunderstood. The reason is simple. When the plastic is selected, the injection molder can determine the weight of the plastic parts, so they can easily weight the machine with this injection weight. In fact, the injection weight is defined as the weight of the plastic injection when empty (not injected into the mold) and is measured rather than calculated theoretically. The rubber used is usually the general gravity of 1.05 hard plastic, plastic parts plastic different from the PS, the specifications on the injection weight to be used after the following conversion. For non-PS plastic injection weight = c * b / 1.05, (b = plastic weight and c = injection weight expressed in PS.) For example, Race steel has a specific gravity of 1.42. 8 ounces of steel.

(1) Choose an injection molding machine with a sufficient weight for injection - You should not choose an injection molding machine with an injection weight that is exactly equal to the weight of the molded part plus the plastic weight of the runner. In the less demanding injection molding, such as toy portrait, the total weight should be 85% of the weight of the injection. In demanding injection molding, such as crystal supplies, then use 75%. The injection weights measured on empty injection, respectively, are small at an injection pressure, whereas high injection pressures require high injection pressures.

For example, Injection molded plastic toy with runway plastic with a specific gravity of 1.38 for rigid PVC (UPVC) 4 ounces, injection weight required for an injection molding machine Injection weight expressed as PS = 4 * 1.05 / 0.38 = 3.04 ounces. Using the 85% guidelines, the injection weight required for Injection = 3.04 / 0.85 = 3.58 ounces.

(2) Injection molding machine with too high injection weight is not acceptable - The total weight of plastic and runner plastic should be between 35% and 85% of the injected weight. The lower limit is due to three considerations: the bending of the plate, the residence time of the plastic in the barrel, and the power consumption per kg of injection molded parts.

Using small molds on small injection molded parts can cause excessive bending of the formwork, causing him to flex (affecting product quality) and even rupturing the formwork.

With a large plastic injection molding machine small plastic parts, melt dwell time is too long will lead to plastic decomposition.

The use of a mold cavity or increase the size of the mold can be used to solve large-scale plastic injection molding machine some of the problems. Reducing the temperature of the barrel also relieves the breakdown caused by the long residence time.

2. Clamping Force

Clamping force is the injection molding machine clamping device is a very important parameter, he is the injection molding machine used in injection molding to resist injection pressure maximum clamping force. Not enough clamping force to produce a fist. Most of the injection molding machines are the clamping force (ton) for the model name.

Should be used in the maximum clamping force below the value of a sufficient clamping force and the projection area of the cavity is proportional to the cavity projection area is the mold projection surface area of the mold parting surface. Here, the ton is the metric ton (equal to 1000 kg). Clamping force estimation in the following ways.

The conservative approach is to multiply the projected area by a plastic-dependent constant. For example, hard plastic injection molding thick-walled 1 to 2 tons/inch thin-wall injection is used 3 to 4 tons/inch 2.

For example: To injection a 79mm diameter general hard plastic cup. The thinnest part of the cup is 0.6 mm. Enough clamping force.

The projected area of the cup (and the runner) is 3.1416 * 7.92 / 4 = 49cm². This cup is thin-walled and has a conservative clamping force of 0.62 * 49 = 30.4T.

Calculate the required clamping force, according to our company's machine specifications table, use the previous grade of the machine.

3. The Projected Area

Projection area is an important injection molding machine model selection parameters, here said the projection area is not only the area of the parts but also includes garbage bits and nozzle area.

The area is generally estimated by dividing the clamping force by a constant. Typical hard plastic thick wall injection constants are 1 to 2 t / in 2 and thin wall injection is 3 to 4 t / in 2.

For the existing beer, casting area calculation should be divided into small regular shape calculation.

      ⑴ d diameter of the circular area of s calculation: s = Лd2 / 4

      ⑵ side length of a square area s calculation: s = a2

      ⑶ a long, b-wide rectangular area s calculation: s = ab

      ⑷ on the bottom of a bottom of the b, high his the calculation of the trapezoidal area