Injection molding costs explained

January 5, 2021

Injection molding cost categories

You have contacted a plastic injection molder and got your quotation. To begin evaluating the quote, wouldn't you like to understand what kind of injection molding costs go into making a quote like that?

Most professional suppliers don't just ballpark a number. On the contrary, precise cost calculation is the backbone of many molding companies. Having a wrong quote can either mean not get the customer or losing money.

Let's take a look at the categories:

Plastic injection material cost

plastic injection pellets
Plastic resin for injection molding

This one is pretty obvious and is a substantial cost for production. Luckily it is pretty easy to calculate for most parts. You know the weight of the part and the runner weight, then there is your total weight per part. Now most molders need to factor in a scrap as well, 2% is a reasonable number for that

It is important for them as well to know if reground material is acceptable to use for your parts. That can decrease your price.

In addition, there can be a cost for drying up the material. This really depends on the material and product you have. In some cases you want a special color, that should also be accounted for.

Ultimately you take all that into consideration and take the raw material price to come to a price. Now you already have the price for raw material, drying, scrap and coloring.

Labor costs in plastics manufacturing

No matter how automated production is, there is always labor involved at some point. In plastic injection molding, the operator cost to handle a machine is often included in the machine rate.

However, your part still needs a quality inspection and packaging. Now, this cost is variable depending on how much testing is needed for your product. Eventually, you will pay for it though.

Machine rate for injection molding machine

arburg allrounder
"Arburg Allrounder" by Lester Public Library is licensed under CC BY-NC-SA 2.0

The machine rate for a machine itself has many factors. In order to save costs, you will take the smallest machine that is still suitable to produce quality parts for yourself. The higher a machine's tonnage, the higher is its rate. Prices for the injection molding machine itself, maintenance, electricity, depreciation, overhead, and labor play a big role in how the rate is calculated.

In case you are wondering how much an injection machine costs. You can get a medium-sized machine without many extras for around $100,000. As with everything, the price will increase with your size and quality requirements.

In order to calculate the cost per part, the injection molder will find out how many parts he can produce per hour. Then simply divide the hourly rate by the number of parts and you are good to go.

Injection molding set up costs

It takes quite a lot of work to get your mold into the machine and start pumping out parts. This can take a few hours. Because of a change in material, warming up, and setting up cooling, this usually has a price of several hundred $. The molder wants to avoid putting in all that effort and just produce a few parts, that is why most of them have this kind of surcharge.

Carton cost for packaging

Probably the easiest cost factor when calculating injection molding costs. You need bags, cartons, and other packaging material to get all your parts ready for shipment.

Injection mold cost

This can easily become the largest cost factor of your part price. In addition, it is the key tool of the whole project. Many molders in plastics manufacturing have good connections with mold manufacturers. Whenever you ask for a quote, they need to contact their supplier as well. In some cases, they have their own internal mold-making department.

The cost here varies so much, it does not even make sense to mention a number. If you want to know a range for most products which you can carry with one arm, take $5,000 to $200,000. The complexity, size, and demands of your product are what drives the price up or down.

Injection molding per part price

lego bricks green
"Lego Bricks" by NickPiggott is licensed under CC BY-NC 2.0

The final and most important number that you get will be the price per part. This is probably the key factor you need to make your decision on, as well as to compare it to other suppliers.

Regardless, it is recommended to ask for a bit more details in your quote. You want to know what kind of mold they are offering to you and how it factors in the costs. Maybe it can get cheaper if you decide to buy the mold somewhere else and pay it separately.

In general, the prices will drop drastically the more parts you need. For a too small amount of parts, it will not be economical to make an injection mold.

For that case, you can check the other article about what kind of plastic manufacturing is suitable for you

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