This blog post continues the Paulson Training series on learning injection molding as a science - Scientific Injection Molding. From the plastic's point of view there are only 4 basic variables in the injection molding process - plastic pressure in the cavity, melt...

A molding machine was then instrumented to ensure that each molding cycle could be examined to check for unintended machine or plastic variations. These instruments measured and recorded the machine timers, barrel temperatures, screw travel, screw RPM, back pressure, injection pressures, and clamp force.  In the mold, three pressure transducers and thermocouples measured the plastic pressures and the mold temperatures. They also measured fill times.

This is largely determined by the complexity and size of the mold, the number of cavities in the mold, and the level of precision required. Undercuts mean side actions, sliders and lifters which means added complexity, more work and higher costs. If you can reduce these features as much as possible and keep your design simple, you will significantly save on lead time and costs.

To get started, simply submit your 3D drawings and project details to our site submission form to get a free injection moulding quote or to speak with an expert from our engineering team.

Injection molding is a manufacturing process widely known for its ability to produce parts cost effectively and consistently. While the process comes with significant cost benefits, unlike 3D printing and CNC machining, it demands a high level of ‘financial commitment.’ In this article we will go through How much does injection molding cost?So, how much can you expect injection molding to cost? Injection molding projects can cost anywhere from $10,000 or less to $100,000. The total cost of injection molding quote is essentially made up of two parts: mould cost + part cost.  Mold Cost (Tooling Cost)The injection molding mold cost is also known as the tooling cost. Tooling refers to the design and manufacturing of the mold used to create injection-molded parts and is often the most expensive component of an injection molding project. Simple molds are typically in the $3,000 to $6,000 range while the price for larger, more complex, higher-production / steel moulds, or multi-cavity moulds can cost from $7,000 and up.  Factors that determine tooling costs in injection molding include:1. MaterialsThe most common materials used to make molds are steel and aluminum, with steel lasting longer. While it’s often said that aluminum costs less, this is not always the case. High-quality but low-cost Chinese steel grades, such as S50C and P20, suitable for rapid tooling and low-volume production purposes, can serve as cheaper alternatives to aluminium. 2. Machining TimeThis is largely determined by the complexity and size of the mold, the number of cavities in the mold, and the level of precision required. Undercuts mean side actions, sliders and lifters which means added complexity, more work and higher costs. If you can reduce these features as much as possible and keep your design simple, you will significantly save on lead time and costs. 3. QuantityQuantity of parts required will impact two fold, first in the tool design itself. If you are looking at very high numbers of parts it might make sense to go with multi-cavity tools, which are larger and more expensive but will bring part costs down. Also the higher the quantity required the better the steel used to machine the cavity, core and inserts will need to be. Low quantities can often be realized using low grade steels or aluminiums’ bringing costs down. 4. TexturesAchieving specific textures or finishes by applying an SPI or VDI finish on the molded part can will impact the costs of your tool. High polished or transparent finishes require both better quality steels and much more work to achieve than a standard polish. To keep costs down, only requests high quality finishes where necessary. Tips to reduce injection mold tooling costsThere are several things you can do to help control and lower costs when it comes to mould making. The top tooling cost reduction tips include: Getting rid of undercuts as they make the tooling process more complicated and costly.Only specify tolerance where necessary.Only requests high quality textures and finishes where necessary.Planning ahead to determine the quantity required to optimize the selection of tooling type (multi-cavity, etc.) and material grade (low-grade aluminium or steels, etc.).Consider Chinese mold manufacturers for steel tooling. Part CostOnce the initial costs of the molds are covered, the cost per unit during manufacturing is relatively low. Typically, you can expect the cost per part to range from $0.20 to $10.00 per piece or higher, depending on the quantity.  Factors that determine injection molding part unit costs include:1. MaterialPlastic pellet resins used in injection molding can range from $1 per kg to $5 per kg or higher, depending on the type of material. Specialty materials, such as glass-filled polymers or elastomers used to achieve specific properties, will typically incur higher costs. To reduce costs, stick to readily available, easy to process material like PP or ABS as far as possible. 2. Cycle timeCycle time or injection moulding time includes setup and running time for each part, this is where the manufacturer’s overheads are. More intricate designs, parts with complex features or larger parts may slow down the time it takes to remove the part from the mold, increasing overall cycle time and costs. Keep in mind that a high-viscosity will require longer injection and cooling time. 3. Secondary OperationsAny additional processes such as assembly, post-molding treatments, or finishing, will increase the unit cost. To keep molding costs and time and down, if it can be done in the tool itself, you should work with your supplier to try and achieve it that way. Tips to reduce the injection molding per part costsThere are several things you can do to help lower the overall per part cost. The top tips to reduce the injection moulding per part costs include: Simplify part geometry to facilitate easier mold release and less wastage.Consider standard resins over specialty materials unless specific properties are essential.Design parts with finishes in mind to minimize additional post-processing steps.

More and more molders are turning to what has become known as "scientific molding" in an effort to systematize their injection molding processes, make them more controllable and make them easily repeatable. As we mention on this site and in many published articles...

This is the third post relating to Paulson injection molding courses and the application of Scientific Molding Packing pressure and gate seal- If you’ve followed our sequence of machine control settings, you’ve learned about fill rate control and the velocity to...

In the November 2012 issue of Plastics Technology magazine, there was an excellent article by Kip Doyle in their "Know How" column (John Bozzelli took a well deserved month off). The title of the article was The Top 10 Reasons Why Molders Fail at Implementing...

The injection molding process for plastic was developed more than 100 years ago. A dynamic growth in all processing methods occurred after World War II. As plastics achieved wider use, it was apparent that production personnel had to learn how to solve part quality and consistency problems. The method used was to determine which of the 20 or so machine controls would solve each type of part problems, e.g. dimensions, weld lines, voids, sink marks, warp, etc. But there seemed to be little or no correlation between machine control settings and most of the molded part problems.

By Donald C. Paulson (As published in Plastics Business Magazine)   More and more we hear the term Scientific Molding used to describe the ideal injection molding process. But what does it mean exactly? Opinions vary widely. Allow me, as a long-time researcher...

It is very important to understand the Velocity to Pressure (VPT) setpoint in order to set up a robust scientific molding process. Not very many years ago, injection molding machines commonly used a hydraulic injection pressure setting and an injection timer to fill...

The most common materials used to make molds are steel and aluminum, with steel lasting longer. While it’s often said that aluminum costs less, this is not always the case. High-quality but low-cost Chinese steel grades, such as S50C and P20, suitable for rapid tooling and low-volume production purposes, can serve as cheaper alternatives to aluminium.

Cycle time or injection moulding time includes setup and running time for each part, this is where the manufacturer’s overheads are. More intricate designs, parts with complex features or larger parts may slow down the time it takes to remove the part from the mold, increasing overall cycle time and costs. Keep in mind that a high-viscosity will require longer injection and cooling time.

So, how much can you expect injection molding to cost? Injection molding projects can cost anywhere from $10,000 or less to $100,000. The total cost of injection molding quote is essentially made up of two parts: mould cost + part cost.

The injection molding mold cost is also known as the tooling cost. Tooling refers to the design and manufacturing of the mold used to create injection-molded parts and is often the most expensive component of an injection molding project. Simple molds are typically in the $3,000 to $6,000 range while the price for larger, more complex, higher-production / steel moulds, or multi-cavity moulds can cost from $7,000 and up.

Quantity of parts required will impact two fold, first in the tool design itself. If you are looking at very high numbers of parts it might make sense to go with multi-cavity tools, which are larger and more expensive but will bring part costs down. Also the higher the quantity required the better the steel used to machine the cavity, core and inserts will need to be. Low quantities can often be realized using low grade steels or aluminiums’ bringing costs down.

Any additional processes such as assembly, post-molding treatments, or finishing, will increase the unit cost. To keep molding costs and time and down, if it can be done in the tool itself, you should work with your supplier to try and achieve it that way.

There are several things you can do to help lower the overall per part cost. The top tips to reduce the injection moulding per part costs include:

A family-owned company created in 1971, Paulson Training is a global provider of workforce development solutions for the plastics industry.

Was browsing through a forum at the Plastics Today website and ran across a thread that brought back memories. Today, Decoupled Molding™" and Scientific Molding are commonplace. But when did these concepts REALLY begin to be used in the injection molding...

In early 1963, Don Paulson, a professor at the General Motors Institute, began a different approach in his research on the causes of mold part variations. The basic premise was plastic processing had to follow the same laws of physics, as all other processes, and that the molding process was simply a four-step sequence of energy inputs and removals.

There are several things you can do to help control and lower costs when it comes to mould making. The top tooling cost reduction tips include:

There was a total of 16 measurements recorded for each cycle. The research continued for four years. Thousands of machine cycles were run and recorded on chart paper to be individually analyzed. Test bars and plaques of various thicknesses were molded and measured. Machine adjustments were made to cause dimensional variations and cause part defects, such as: voids, sink marks, burn marks, and flash. In nearly every case, the defect could be directly attributed to one or more of the four basic plastic processing variables.

Once the initial costs of the molds are covered, the cost per unit during manufacturing is relatively low. Typically, you can expect the cost per part to range from $0.20 to $10.00 per piece or higher, depending on the quantity.

Each of these molding steps would be governed by the laws of physics. First, the Laws of Heat Transfer; second, the Poiseuille fluid flow law; and third, the Equation of State for Plastic. These three equations applied to the molding process required only four measurements during each molding cycle. Those four measurements are the melt temperature, the fill time, cavity pressure, and the mold temperature.

First, the research was proof that plastic processing follows the same physical laws as all other materials, and secondly, the properties and characteristics of the molded parts are determined by the four basic plastic variables.

Injection molding is a manufacturing process widely known for its ability to produce parts cost effectively and consistently. While the process comes with significant cost benefits, unlike 3D printing and CNC machining, it demands a high level of ‘financial commitment.’ In this article we will go through

In the past, the training of competent molding personnel has required years of experience on the production floor. This new understanding of molding as a science based technology allows personnel to learn injection molding from the plastic’s point of view and understand the actual causes of part defects. Molders must still learn machine setup, the operation of each machine control and the effects of each machine control on the plastic. The raw material must still be monitored, and the machines must be maintained, but the decisions on best control settings, best cycles and how to solve molded part problems will be science-based. Experience has shown that learning plastic processing from the plastic’s point of view is far faster and more effective than the traditional method.

Over the years, numerous companies and researchers set out to determine which machine controls to use to eliminate each specific part problem. An example was an Eastman Kodak research project in 1962 to establish how to control specific dimensions in their Instamatic film cartridge. In a design of experiments project, and after six months of molding and measuring, the report concluded that the dimensions were being affected by:  barrel zone temperatures, screw RPM, injection pressures, holding time, fill time, and back pressure. In the conclusion, the author states, “all of the above machine settings had an effect on part dimensions and further study would be required”.

Achieving specific textures or finishes by applying an SPI or VDI finish on the molded part can will impact the costs of your tool. High polished or transparent finishes require both better quality steels and much more work to achieve than a standard polish. To keep costs down, only requests high quality finishes where necessary.

Plastic pellet resins used in injection molding can range from $1 per kg to $5 per kg or higher, depending on the type of material. Specialty materials, such as glass-filled polymers or elastomers used to achieve specific properties, will typically incur higher costs. To reduce costs, stick to readily available, easy to process material like PP or ABS as far as possible.

How much will my injection molding project cost?Estimate the cost of your injection molding project with us. HLH Rapid has over 20 years of experience in building custom tools and plastic injection moulded parts for engineers and industrial designers in a wide range of industries from automotive, medical, electronic devices and more. We can build low-cost and high quality tools from a wide range of material grades and well designed tools.To get started, simply submit your 3D drawings and project details to our site submission form to get a free injection moulding quote or to speak with an expert from our engineering team.

Estimate the cost of your injection molding project with us. HLH Rapid has over 20 years of experience in building custom tools and plastic injection moulded parts for engineers and industrial designers in a wide range of industries from automotive, medical, electronic devices and more. We can build low-cost and high quality tools from a wide range of material grades and well designed tools.

For decades, the idea that specific machine control settings would directly correlate to specific part problems and their solutions seemed ingrained in the industry. However, that was wrong.

For decades, the idea that specific machine control settings would directly correlate to specific part problems and their solutions seemed ingrained in the industry. However, that was wrong.