Injection molding simply involves injecting molten plastics into molds to make parts that can be used for the production of bigger materials. Though this sounds simple enough, molds could be expensive to produce especially if the plastic injection mold used for producing the molds is expensive. Understand the factors that affect the cost of injection molds is a very important step that will help ensure you run a profitable plastic mold manufacturing business.
So what factors affect the cost of injection molds?
1. Complexity of Part
The complexity of your injection mold should be the first factor you have to consider. As is normal to most engineering machines, the complexity of design will greatly affect the cost of the machine. Injection parts with a lot of undercut features will generally be more expensive due to the cost of tooling required. If the corners must be sharp, the cost of tooling required for it will be on the high side.
In addition to that, if the position of the sharp corners on the mold prevent the use of a round cutter for part machining, an alternative secondary procedure called EDM will have to be used. The making of the undercut features will consume productive time that could have been used for other works. It may also require a lot of adjustments being made to accommodate the changes.
The complexity of part you need will affect how much you will part with for the injection mold. So the more complex the parts, the more expensive the mold will be.
2. Type of steel
They are different types of steel for different occasions and different budgets. For you to factor-in this, you must clearly understand what you are working with. In plastic injection mold manufacturing, the characteristics of PVC when in contact with a particular type of steel is important. Things like the type of reaction that occurs between the gasses is very important.
Mold life will also affect the cost of material used in making the mold machine. The more durable the steel, the higher the mold life and the higher the cost of steel used. Other things to consider are required cycle time, type of surface finish and how many parts are expected in production.
Types of steel used by plastic injection molding companies include H13, P20, Alloy, Copper, S136, 1.2344/1.2343, 1.2311/1.2312 and Be-copper. Poor steel selection can result in cracked cavity or core causing it to wear out. The better the quality of steel needed, the more you will have to pay for your mold machine.
3. Surface Finish
For your plastic injection work, the type of surface finish you desire to achieve goes a long way to affect the cost of the injection mold. If you are interested in high-quality surface finish, it will cost more because most of the work will be done manually by hand. Otherwise, machine finish can be used which will not cost so much. Hand-finishing takes a lot of time and effort and must be factored into the cost of the machine.
One important thing you must have at the back of your mind before making this choice is the role the surface finish will play in your final product. If you are the type of plastic injection mold manufacturer who is interested in using the product surface to add beauty to products, you will have to go with hand finishing because it will improve the aesthetics of your product.
Beautiful finishing can also help you cover up for little imperfections, improved paint and sticker adhesion, and improved trapped gas escape from your plastic.
4. Size and Number of Cavities
Every plastic injection mold manufacturer must understand how the size and number of cavities affect the cost of an injection mold. Talking about size, you must understand that the size of the plastic part to be produced by the injection mold machine is directly proportional to the mold size required to produce it. Larger molds require larger amounts of building space and expensive equipment required to work on them.
The nature of job of your customers will go a long way to determine the number of cavities used. Let’s take for an example, a customer’s order for 1 part will be constructed as 1 cavity mold producing only 1 part per machine cycle. But a customer’s order for more than 1 part, will be constructed as a 2, 4, or 8 cavity mold producing several parts per machine cycle.
It is important to note that multi-cavity mold will cost more than single cavity mold.
5. Location of Mold Supplier in China
Every Chinese Injection Molding Company has a somewhat different overhead cost required in producing Mold Machines. These overhead costs can come in different ways but most often than not, will depend on the location of the plant. Your mold manufacturer may not tell you this but it is important you figure it out.
Different provinces in China have unique minimum wages, so this must be factored in to the cost of producing the equipment. Areas with higher minimum wages must as a matter of fact, pay their staff more while those with lower minimum wages will pay their staff less.
Another important aspect to take note of is transportation. Since these companies must transport their products to sea ports, nearness to the sea will also imply lower cost of transportation and hence lower cost factored into the price of the plastic injection mold. Companies in the hinterland will have to pay more in moving the mold machine to the sea and will probably factor that too into their cost of production.
Local government regulations in the provinces may also affect the cost of the machines. All of such companies in China must also account for the waste materials they produce hence may have to pay environmental protection levies.
Tooling depends to a large extent on a number of cavities. Injection Molds that require number of cavities will be more expensive because of the higher the number of cavities, the more expensive the tool. This alone can raise cost by up-to 60 percent.
Few cavities need few tooling work and hence, low cost in manufacturing. It is also good to note that increased cavity leads to more parts being produced per hour which will in turn, reduce machine cost per part.
Under tooling, you must also consider the size of parts needed. Large parts require large molds which in effect will take more time to produce hence increasing the cost of the mold. It is necessary you inform your mold manufacturer what you want to use the injection mold to produce so that he can advise you on the type of tooling required.
In a nutshell, you should not just jump out into the market to purchase a mold machine from plastic manufacturing companies in China without critically analyzing the factors above. It may only take you a couple of hours to apply the factors above but it will surely save you more money than you can imagine.