Momentum

Custom Injection Molding

Custom Plastic Injection Molding

Our rich experience as a USA plastic injection molding company includes production capabilities for many different industries, plastic materials, and specialty add-ons for your custom plastic parts.

Our focus is on production runs of 100 to 100,000 units per order. We know every custom injection molding project is different, but every MSI Mold customer enjoys our key values:

  • High quality custom plastic injection molds and custom parts with reliable on-time deliveries
  • Outstanding attention to customer needs through advanced quality planning
  • Fast quotes and delay free communication
  • Friendly and knowledgeable customer service

Injection Molding Projects Start With A Mold

Receiving high-quality injection molded parts starts with a quality built mold. Molds for plastic injection require a significant investment so we’ll work with you every step of the way to ensure you’re familiar with the different types of molds that are available for your project. We’ll make sure you’re completely informed before you invest in your tooling. Below we provide you with a valuable understanding of basic injection mold construction types and the benefits of each.

What Is a Custom Plastic Mold?

A custom plastic mold is a specialized and unique piece of tooling that’s used during the injection molding process to manufacture a specific product to meet customer requirements. If you need to manufacture hundreds or thousands of quality custom plastic parts, making a plastic mold that meets your exact requirements for part quality, manufacturing demand, and product pricing is essential.
Building your custom mold is the first step in your injection molding supplier's process. A quality-built mold demands highly skilled people and high-tech machinery and software. Our mold design and injection molding experts work with you each step of the way to ensure you receive a top-quality mold that meets the specific requirements that are unique to the part you need manufactured.

Plastic Injection Molding Challenges

Two of the biggest challenges with plastic injection molding projects are the cost and lead time. At MSI Mold, we overcome these challenges by building all injection molds in-house. We have also developed rapid tooling systems that reduce costs and improve lead times without sacrificing quality.

Having your mold and injection molded parts made in the United States can offer consistent quality and lower overall costs. Modern USA plastic injection molding companies use high-tech equipment and offer reliable technical expertise. In addition, if you source your project to a reputable USA injection molding supplier they will consistently use high-quality materials unlike many offshore suppliers.

When you source injection molding suppliers in the USA, you significantly lower transportation expenses and have readily available access to customer service and communication. Interaction with our injection molding experts throughout the process ensures a seamless sourcing experience production of the best possible molded plastic parts.

Injection Molding Process

Plastic injection molding requires three primary components – an injection molding machine, a mold, and raw plastic material. Molds for plastic injection consist of high strength aluminum and steel components that have been machined to operate in two halves. The mold halves come together inside the molding machine to form your custom plastic part.

The machine injects molten plastic into the mold, where it solidifies to become the final product. The injection molding process is actually a complex process with many variables of speed, time, temperatures and pressures. The complete process cycle for making each custom part can range from no more than a few seconds to several minutes. Below we offer you a very brief explanation of four steps of the molding process.
Step 1

Clamping

Before the plastic is injected into the mold, the machine closes the two halves of the injection mold with tremendous forces which prevent the mold from opening during the plastic injection step of the process.
Step 2

Injection

Raw plastic, generally in the form of small pellets, is fed into the injection molding machine at the feed zone area of a reciprocating screw. The plastic material heats up by temperature and compression as the screw conveys the plastic pellets through heated zones of the machine barrel. The amount of melted plastic that is conveyed to the front of the screw is a strictly controlled dosage because that will be the amount of plastic which will become the final part after injection. Once the proper dosage of melted plastic reaches the front of the screw and the mold is fully clamped, the machine injects it into the mold, pushing it into the endpoints of the mold cavity under high pressures.
Step 3

Cooling

As soon as the molten plastic contacts the internal mold surfaces, it begins to cool. The cooling process solidifies the shape and rigidity of the newly molded plastic part. The cooling time requirements for every plastic molded part depends on the thermodynamic properties of the plastic, the wall thickness of the part, and the dimensional requirements for the finished part.
Step 4

Ejection

After the part is cooled inside the mold and the screw has prepared a new shot of plastic for the next part, the machine will unclamp and open the plastic injection mold. The machine is equipped with mechanical provisions that work with mechanical features designed within the plastic injection mold to eject the part. The custom molded part is pushed out of the mold during this stage and once the new part is fully ejected, the mold is ready for use on the next part.

Tooling & Part Costs

Target Cost Planning for Custom Injection Molding

The cost of custom plastic injection molding projects for long-term production varies greatly. Simple mold tooling may range anywhere from $3,000 to $10,000. More complex, multi-cavity or high-production injection molds cost significantly more, from tens of thousands to hundreds of thousands of dollars. As explained in our cost relationship graph below, there is an inverse relationship between tooling costs and production part costs. Calculating the total cost for tooling and injection molded part prices involves assessing many factors, such as:

Factor #1

Part Complexity

Part design features such as sharp corners, thin ribs, or undercut features require more expensive tooling and, frequently, a secondary EDM machining process. During a quote consultation we will point out part design considerations that can reduce overall costs when possible.
Factor #2

Mold Construction

Of the two primary categories of injection molds, insert style molds will cost significantly less to create than free-standing molds. Insert style molds allow us to only make the mold components that are custom for each part shape, and there is no sacrifice of part quality, mold quality, or mold life.
Factor #3

Number of Mold Cavities

The lower the number of mold cavities, the fewer parts will be produced per machine cycle, meaning a higher cost per part. Though a one cavity mold will be less expensive, there is an inverse cost relationship between adding mold cavities and the cost of the parts.
Factor #4

Part Size

Simply put, the larger the part, the higher the costs will be for the injection mold and the parts. Small plastic parts only require small machinery to make molds and parts, and large parts require large machinery to produce the molds and parts. The machinery & equipment costs for injection molding companies are proportionate to the size of the equipment.
Factor #5

Material Choice & Part Weight

The plastic material chosen for a part not only affects the weight of the part, but it also impacts production rates, which is a considerable cost factor for custom injection molding. Heavy thick-walled parts will cost a lot more to produce than parts that are designed with weight reducing features. When choosing the material for your custom molding project, consider the part’s function, application and environment, as well as the following features of the raw plastic: -Flexibility for function -Impact strength against breakage during use -Environmental temperatures -Cost and availability -Recyclability requirements Your plastic material’s density is a vital element to consider as raw plastic material ranges from $1 to $25 per pound. In addition, different families of plastic materials can process faster or slower within injection molding applications which directly affects the long term cost of the parts.
Factor #6

Cycle Time

The length of time it takes a molding machine to finish a complete production cycle from mold closing through ejection of the parts is called cycle time. The cycle time (amount of time it takes to create a part) is the single largest cost factor in custom plastic molding aside from plastic material costs.
Factor #7

Extra Add-On Costs

Specialty packaging, secondary operations like pad printing and extra machining contribute to a higher cost for custom plastic parts. In very low order quantities these add-on costs can be very expensive

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Selecting A Plastic Material For Your Parts

There is a wide variety of plastic material options for custom injection molding. It is most helpful for product engineers and designers to focus on the functional utility and working environment of their parts when selecting a plastic material. Talk to your injection molding supplier about these to help narrow down the right plastic material family for your custom injection molding project.

At MSI Mold we are happy to provide consultation to help customers find the right plastic material choice for their custom molded parts.

Choosing the right material hardness depends upon the part’s intended use, environment, required abrasion resistance, and how a user will interact with it. Plastic hardness is measured and represented by number values on “shore 00”, “shore A” or “shore D” scales. For example, a gel shoe insole might have a hardness of “30 shore 00”, but a construction worker plastic hard hat might have a hardness of “80 shore D”.

Different from hardness, flexibility or stiffness indicates how much or little a material will resist stress. Impact resistance is another specification to consider for plastic materials that might see tough conditions across wide ranging temperatures.

The mass or density properties of plastics can vary widely. In turn, for any given part volume in cubic cm the part weight can vary widely simply by picking a different plastic material. Keeping in mind that plastic raw materials are sold by the pound, unnecessary costs can add up very quickly throughout a product life cycle if the wrong plastic material is chosen.

Fitness for the product application should be the primary concern when choosing the plastic type for a particular custom molded part. Cost per pound should only be considered where there is a choice of suitable materials.

Common Plastics Used For Injection Molding

We use many thermoplastic materials for your custom plastic part needs. Many of the plastics listed here are always in stock and ready for production. If your product needs a custom color we can help!
ABS
Acrylonitrile Butadiene Styrene
ASA
Acrylonitrile Styrene Acrylate
HDPE
High Density Polyethylene
LDPE
Low Density Polyethylene
PA 6
Nylon Type 6, Aliphatic Polyamide
PA 66
Nylon Type 66, Aliphatic Polyamide
PC
Polycarbonate
PC/ABS
Polycarbonate + Acrylonitrile Butadiene Styrene
PMMA
Acrylic
PP
Polypropylene
POM
Acetal, Polyoxymethylene
TPE
Thermoplastic Elastomer
TPO
Thermoplastic Polyolefin
TPU
Thermoplastic Polyurethane

Equipment We Use

As a reputable plastic molding company, MSI Mold uses a variety of technologies for designing and manufacturing molds and custom plastic parts, including but not limited to:

Modern CAD Software

Computer-aided design software allows the manufacturer to take a simple 2D drawing and create an optimized 3D CAD model for your custom parts and injection molds. Our knowledgeable and friendly injection molding experts put their expertise to work with high-tech design and simulation software. We always use the latest software technologies available to reduce lead times, unexpected quality problems, and overall costs for our customers.

In-House Mold Manufacturing

In-house mold manufacturing is a very important capability for injection molding companies to have. Manufacturers and buyers searching for injection molding suppliers can benefit greatly on tooling cost, lead times, and single source responsibility for overall quality by only working with suppliers that manufacture customer molds in-house and in the USA.

At MSI we have a full-service mold manufacturing area inside our facility. We control every step of our customer mold builds to prevent loss of time and unexpected quality problems.

All-Electric Servo Injection Molding Machines

At MSI Mold, all of our injection molding machinery is modern all-electric servo driven. That means our machines use 50-70% less energy than traditional hydraulic pump motor driven molding machinery of the past. We are proud to say that in addition to being environmentally and workplace cleaner, our machinery is the most precise and repeatable that is available in our industry.

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