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What Is The Composition Of Injection Mold Cost

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The mold industry has varying levels of manufacturers, ranging from those with very sophisticated equipment to those with quite rudimentary setups, all coexisting in the industry. As a result, purchasing personnel often encounter vastly different quotes for the same project from different factories, which can be quite confusing!

If you are a buyer of injection molds or commission injection molded products, you might be most interested in:

  • How to manage the procurement of injection molds?
  • How to choose the best mold supplier?
  • How to purchase molds that are both good quality and reasonably priced?

Through this article, FirstMold aims to help more buyers by providing a simple explanation of the components of mold pricing, enabling you to choose the most suitable mold manufacturer and quote.

Cost Composition of Injection Molds

Injection mold costs are divided into explicit and implicit parts.

The explicit part refers to the direct costs that are visible, such as material costs, processing fees, design fees, management fees, patent allocations, and profits.

Based on experience, the prices for molds consisting of explicit cost components are typically as follows:

Mold Price = Material Costs + Design Fees + Processing Fees + Taxes + Testing Fees + Packaging and Transportation Costs + Profit. The usual proportions are:

  1. Material Costs: Materials and standard parts constitute 15% to 30% of the total injection mold cost.
  2. Processing Fees: 20% to 30%.
  3. Design Fees: 10% to 15% of the total mold cost.
  4. Testing: For large and medium-sized molds, manufacturers control it within 3%. For small precision molds, it will be less than 5%.
  5. Packaging and Transportation Costs: Manufacturers calculate this according to the actual expenses or at 3%.
  6. Taxes: 15%.
  7. Profit: 5% to 15%.

The implicit part refers to indirect costs that do not appear during mold production but are related to costs incurred when the mold is put into mass production later. For example, the lifespan of a mold can affect subsequent investments.

Material Costs in Injection Mold Manufacturing

The materials for injection molds include various types of steel and non-metal materials. Mold factories purchase these directly. The material cost of an injection mold also depends on the structure of the mold. We have detailed the components of a mold in the article “Injection Mold Structure.” From a cost perspective, we divide the injection mold into four parts: the mold base, runners, standard components, cores and cavities.

The first three categories are from professional manufacturers, while typically, cores and cavities are the key components that mold manufacturers make it themselves from purchased steel.

The composition of the material to be purchased in the mold
The composition of the material to be purchased in the mold

Standard Mold Base

The cost of the mold base accounts for about 15-25% of the total material cost.

Some standard mold bases - Injection Mold Cost
Some standard mold bases

1. The cost of the mold base mainly depends on the manufacturer and brand.

High-quality mold base manufacturers and brands choose better-quality steel, ensured by large volume purchases directly from steel manufacturers through official channels, ensuring genuine materials. Correspondingly, their processing equipment is also top-tier global brand equipment, guaranteeing machining precision and design requirements. Finally, because design talent is concentrated and there are many professionals, personnel costs are also higher. Thus, the prices of mold bases from good manufacturers are generally higher than those from smaller ones.

Of course, for some standard molds made in large volumes, the scale effect means that large mold base manufacturers still have a significant competitive advantage in pricing. However, overall, you get what you pay for.

Due to different part shapes, the corresponding mold structures also vary. For instance, molds with undercuts or lateral holes must have a slider structure, and molds with internal gates using three-plate molds are more complex than those using two-plate molds with external gates, leading to higher production costs for the mold base.

2. Machining precision and material, with precision being the main factor.

Ordinarily, the machining precision of standard mold bases is 0.03-0.05mm, while that of high-precision mold bases is 0.005-0.01mm. Different precisions require different base equipment, and machining time can increase geometrically. Simply put, the cost of high-precision mold bases can be 2-3 times that of standard ones. Of course, high-precision mold bases are the foundation of high-precision molds. They ensure high dimensional stability, high direct pass rates, stable operation, and relatively lower costs of molding defects.

Hot Runner Systems

Runners in molds are typically categorized into cold runners, hot runners, or semi-hot runners. Generally, only hot runners need to be purchased externally, while the other types are usually manufactured within the mold factory itself.

In molds with hot runners, the cost of the runners often accounts for 40 to 50% of the total material costs of the mold.

Hot runners are divided into two types: sprue gating and valve gating.

In production, the cost of hot runners is mostly calculated based on the number of hot runner nozzles. In the industry, international leading brands (such as Husky and Mold-Masters) typically price hot runner nozzles between $2,000 and $4,000 each, depending on the design and application.

Additionally, one should not forget another significant cost component, which is the temperature control system. However, many temperature control systems are interchangeable, and large injection molding factories have their own invested equipment, so this cost might not necessarily be included in the quotes from injection molding factories.

Mold Plates, Cores and Cavities

Plates, cores and cavities are typically manufactured by mold factories using materials they purchase. Let’s discuss the cost of purchasing steel for these components first.

Mold Steel

Common brands of mold steel include ASSAB from Sweden, Böhler from Austria, and Daido Steel from Japan. There are also many frequently used steel types from Germany, France, and the USA.

The quality of steel on the market varies significantly. Unlike the quality-stable steel produced by major steel mills, many smaller mills produce steel that is underweight and of unstable quality with higher levels of impurities like sulfur, phosphorus, and nitrogen, which can lead to numerous quality issues. Moreover, many traders even mislabel products from smaller steel mills to match those of major mills, and these are then sold on the market. This results in significant price disparities.

Therefore, purchasing personnel within mold manufacturers need to have the ability to distinguish between different steels and ideally establish direct contacts with major steel mills to stay updated with the latest industry price information.

The choice of steel directly affects the lifespan of the mold.

Based on the quality of the steel, injection molds can be categorized into: Grade A (over 3 million injection cycles), Grade B (over 1 million injection cycles), Grade C (over 500,000 injection cycles), and Grade D (less than 500,000 injection cycles).

The longer the warranty for the mold in terms of the number of cycles, the higher the price of the mold. Mold manufacturers need to select different types of mold steel based on the warranty cycles, the properties of the plastic being molded, the shape of the molded parts, and the mold structure. These factors include wear resistance, chemical corrosion resistance, etc. Thus, the more injection cycles required by the injection mold, the higher the price.

Processing Procedures

The primary procedures include the manufacturing of mold plates, mold cores, mold cavities, and runner plates. Depending on the type of mold and precision requirements, the necessary equipment and labor hours vary.

The impact of processing steps on the workload is greatly influenced by the design of the mold.

Firstly, the shape of the molded parts affects the workload. For example, molds with undercuts or lateral holes require a slider structure, which complicates the design and increases the workload. Similarly, molds for threaded caps with a gear and rack rotational ejection structure are more complex and thus more expensive than those with a simple ejector structure.

Secondly, different designs for the same molded parts can lead to variations in structure and thus in the processing workload. Therefore, top mold factories often have more rational and optimized mold structure solutions. It is common practice for major companies to have experienced and skilled mold engineers review the rationality of mold structures, which is very helpful for procurement personnel.

Mold Plate Processing Steps:

  • Rough machining of the mold plate
  • Drilling of water lines and tapping
  • Precision grinding of the mold plate
  • Fine machining
  • Fitting processes (venting, oil grooves, etc.)

Cavity And Core Processing Steps:

  • Rough grinding
  • Rough machining
  • Drilling of screw holes
  • Heat treatment (usually outsourced)
  • Precision grinding
  • Fine machining
  • Cavity polishing
  • Assembly

Different stages of the process utilize different types of equipment

On the other hand, processing fees are closely related to the depreciation and utilization rate of the equipment, which directly correlates with the brand and model of the equipment used.

Mold processing equipment from advanced manufacturing countries such as Germany, Switzerland, Italy, and Japan is generally expensive. Please check the CNC machines.

The processing equipment used in each process of injection mold
The processing equipment used in each process of injection mold

Under the same brand, due to differences in manufacturing precision and speed, the price gap between normal and better models, as well as between ordinary industrial grade and super precision grade, can be substantial. The price difference for machines performing the same process can range from 7,000-8,000 dollars to 300,000-4,000,000 dollars. Therefore, procurement personnel should have a good understanding of the brands and models of basic mold processing equipment.

Different equipment incurs different costs

The higher the precision of similar equipment, the higher the investment cost, and consequently, the higher the labor costs. However, this depends on the precision requirements confirmed during the design phase to avoid over-specification.

Higher processing precision requires longer working hours and therefore increases the total cost

In practice, it is possible to negotiate labor costs for various types of equipment with the mold manufacturer in advance, based on the design, to agree on the required labor hours and establish the processing costs of the mold before development starts.

Labor Costs

Here, we’re referring to indirect expenses (direct machine operators’ expenses are generally included in processing fees), mainly design fees, which typically account for 5% to 10% of the total mold cost.

Mold design begins after product design is completed and includes the following:

  1. Mold Structure Design: This involves analyzing customer requirements (product feasibility analysis, production capacity requirements), mold flow analysis, runner analysis, waterway design, parting surface design, etc.
  2. 2D/3D Drawing Creation: Creating detailed 2D and 3D drawings of the mold based on the design specifications.
  3. Feasibility Analysis of the Mold: Assessing the feasibility of implementing the mold design.

Design fees are essential for ensuring that the mold meets all requirements and specifications, including functionality, manufacturability, and efficiency. These fees cover the expertise and time required for mold designers to develop precise and effective mold designs that meet the needs of the customer’s project.

Management Costs

The types of management expenses in a company’s operations are very diverse, including employee salaries, depreciation, office expenses, and more. These costs are somewhat apportioned into the mold costs.

However, in daily operations, the calculation of management fees is not typically conducted based on detailed financial items. This approach avoids overly complicated calculations that are not conducive to straightforward computation. Moreover, many detailed items might be considered part of the company’s confidential business operations and are not suitable for public disclosure. Therefore, a common practice is to calculate a percentage based on the previous year’s total management expenses divided by the total main operating revenue, and this percentage is used for pricing.

For example: If in 2023, the total management expenses were 10 million and the total main operating revenue was 100 million, then the management costs for that year would be calculated at 10%.

Profit

Profit is typically calculated according to a proportion agreed upon in advance by both parties.

In the interest of fostering the development of the company and establishing a long-term, healthy, and sustainable partnership between both parties, FirstMold has a modest wish: to ensure a normal profit margin within the industry and prevent cutthroat competition. The hope is to determine pricing by exploring opportunities in materials, technology, processes, and efficiency while ensuring the normal profits of the mold company.

In projects aimed at reducing injection mold costs, it is important to use scientific methods to identify and eliminate unnecessary losses and waste. It is also crucial to actively research and implement innovative technologies and processes to enhance production efficiency. Furthermore, employing lean production management, and methods such as 6S and 5S, can effectively reduce wastage of working hours and minimize machine downtime.

With the advent of the new era of smart manufacturing, we should actively participate and use new artificial intelligence technologies to reduce labor costs.

Scientifically Reducing Injection Mold Costs

One of the main factors affecting injection mold costs is whether the plastic part design is rational. Product designers should consider not only the functionality of the plastic parts but also the feasibility of the plastic process and subsequent assembly, as well as the cost of the parts.

Here are some classic cases:

1. The Impact of Plastic Part Fillet Design on Injection Mold Costs

A small card cover plastic part made of LCP material often breaks at the snap-fit location after several tens of prototypes during the trial molding process, causing trial interruptions. Mold assembly staff frequently had to disassemble the mold to clean up the broken snaps.

A small card cover plastic part with sharp corner
A small card-covered plastic part with a sharp corner

The main reason for the snap-fit breakage is stress concentration at the snap-fit during injection molding and insufficient draft angle at the sides of the snap-fit. Merely solving this from the mold side by repeated polishing does not address the root cause. Repeated trial moldings increase the trial cost, and the workload for mold polishing and assembly, thus increasing the manufacturing cost.

In mold processing, fillets or corners need EDM (Electrical Discharge Machining) to meet the shape of the plastic parts. Designing reasonable fillets at corner positions can reduce EDM operations and related material costs, significantly saving on mold processing costs and time.

2. The Impact of Plastic Part Wall Thickness on Injection Mold Costs

The wall thickness of plastic parts indirectly affects injection mold costs and is analyzed from two aspects:

1) Too thin walls can cause short shots, making production unstable and increasing the trial molding costs within the mold cost.

2) Too thick walls can lead to sink marks and varying degrees of deformation in the parts. To address these issues, the cooling time in the injection molding cycle is increased to reduce these defects.

Case 1: The impact of too-thin wall thickness on injection mold costs.

The picture below shows a thin-walled annular plastic part where the wall thickness at the thread in the middle is 0.25mm, the upper circle is 0.6mm, and the lower circle is 0.4mm. The mold uses a large gate on the edge of the lower circle. The mold underwent more than ten trial runs, with the most challenging issue being the weld lines at the thread due to inadequate venting, causing defective parts.

Short shot defect in thin wall thickness part
Short shot defect in thin wall thickness part

Due to the thin wall thickness at the thread, which cools quickly, the final flow of the material ends at the thread position. From a structural analysis by the development department, there were no issues. From a production standpoint, the wall thickness was designed too thin, increasing the number of trial runs without resolving the issue. Finally, without altering the blueprint dimensions, tolerances were analyzed, extra material was added to the wall thickness to bring it to the upper tolerance limit, and mold dimensions were adjusted to address the filling issue.

Case 2: The impact of uneven wall thickness on injection mold costs.

As the picture below shows, the top wall thickness of the part is 2mm, while the side wall is only 1mm. Mold flow analysis confirms the deformation trend and amount, which tends to deform towards the thicker section. Therefore, during the development and design stage of the plastic part, the uniformity of the wall thickness should be considered to reduce the amount of deformation.

Deformation of plastic parts with uneven wall thickness
Deformation of plastic parts with uneven wall thickness

On the mold side, the plastic part could be adjusted by changing the size or position of the gate, continuously verifying the optimal amount of deformation or adding more fixtures to correct deformation. This increases the cost of trial molding and auxiliary tools, as well as the labor intensity of the production operators.

In injection molding production, increasing the cooling time in the molding cycle can reduce deformation, but this is a symptomatic solution and does not fully resolve the deformation issues. Passing the problem to the next process invisibly increases the number of mold adjustments, prolongs the injection molding cycle, reduces production efficiency, and raises production costs, which is not advisable.

Mold Factors Affecting Injection Mold Costs

1. Reasonableness of Mold Design

Mold designers vary in experience and skill level. To address issues during the design process, the most effective method is to conduct reviews of the plastic parts and molds.

As shown in the picture, due to several slots in the plastic part, the slots consist of four types of inserts A, B, C, D, with the smallest insert A measuring 45×0.6×65mm. From the design dimensions of the inserts, all four belong to thin inserts. After trial molding, it was found that no matter how the molding process parameters were adjusted, it was impossible to control the flash (burrs) at the insert locations. Regarding the plastic part flash (burrs) issue, repeated mold adjustments, disassembling, and reassembling of the mold, and trial moldings invisibly increased the manpower costs for mold assembly and trial costs, and the problem remained unsolved. After redesigning the four inserts into two, the mold flash was significantly improved.

Mold insert design drawing
Mold insert design drawing

Another scenario is design waste. For market development or experimental needs, some newly developed plastic parts only require 2,000 pieces, and a mold life of 5,000 pieces would suffice. Designing a mold for a lifespan of 100,000 cycles in such cases is excessive and constitutes design waste.

2. Purchase of Standard Parts

The promotion of mold standard parts is mainly to shorten mold manufacturing time and reduce mold processing costs, achieving cost-effective results. Currently, there are many suppliers of mold standard parts. If one is tempted by low prices and makes hasty purchases, it is the mold companies and mold users who suffer the greatest losses, not the suppliers.

To reduce injection mold costs, standard parts should be used as much as possible during mold design. It is best if the specifications can meet the standards of multiple suppliers, allowing for comparative pricing from multiple vendors, enlarging the selection space, and helping to reduce injection mold costs.

3. Reducing the Number of Trial Moldings

Mold companies calculate the processing fees for molds based on the number of days from when the order is received to when the mold is qualified and leaves the factory. If a mold requires multiple trial moldings before it can be delivered for use, not only are penalties imposed according to the contract, but the longer the mold stays in the factory, the more processing fees and trial costs accrue. Thus, multiple or uncontrollable trial moldings are a significant blind spot in injection mold cost control.

Reasons for multiple trial moldings include:

1) The mold design was not thoroughly reviewed by a team, leading to unreasonable structures that require multiple corrections after trial moldings;

2) The mold design was good, but the mold processing was inadequate, leading to unnecessary increases in trial moldings and mold costs;

3) The best molding process and injection machine were not selected during the trial, resulting in a well-made mold but suboptimal injection molded parts;

4) Insufficient understanding of the physical properties of the plastic, and incorrect selection of shrinkage rates, causing repeated mold corrections.

4. Mold Materials

Large air conditioner appearance parts or transparent parts require a lot of mold material, and the cost of mold materials accounts for a significant proportion of the mold price. Choosing stainless steel as the mold material makes the material costs high and the mold unit price high, eliminating competitive advantage. Choosing inferior mold steel results in inadequate surface polish and wear resistance, and the plastic parts fail to meet customer requirements. To reduce mold costs while meeting customers’ demands for high gloss on the plastic part surfaces, inferior materials are processed and surface coating treatments are applied to the mold cavity surfaces to enhance the mold’s gloss, rust resistance, and wear resistance.

Factors in Injection Molding Production Affecting Mold Costs

Injection mold costs rarely focus on information related to injection molding production. For a company producing products, it is not just about the mold making money, but about the final profitability of the product. In the injection molding production process, the mold is the most crucial link, and the stability of mold production is reflected in injection molding production.

A mold often needs to be disassembled for repairs due to broken ejector rods, mold collapse, oil contamination, rusting, unsuccessful ejection, broken inserts, burnt sliders, deformation, etc. This increases mold maintenance costs and injection molding production raw material costs, machine downtime costs, and other hidden costs, which are ultimately passed on to the product.

Conclusion

Managing injection mold costs is not solely the responsibility of mold manufacturers but also requires cooperation from product design companies and injection molding production departments to minimize injection mold costs and design more rational, high-quality molds. Reasonable plastic part design, minimal changes to plastic part designs, advanced mold design, and sensible material selection can all significantly reduce mold costs. To produce quality products, product designers, mold engineers, and injection molding production departments need to maintain good communication.

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