Optimize Your Production with MUD Injection Molds for Lean Manufacturing

Boost Productivity and Cut Costs with Our Master Unit Die Quick-Change System—Interchangeable Molds for Optimal Efficiency.

Our MUD Injection Mold Types

The Master Unit Die Quick-Change (MUD) System includes a straightforward frame designed to hold various inserts. There are four types of frames, tailored to the part size and production volume:


Accommodates a single standard insert.


Holds a standard double insert.

Double H-Frame

Fits four standard inserts.


Designed for side-by-side double inserts.

Available MUD Mold Insert Types

Standard Insert

T-style Insert

Standard insert molds are cost-effective and suitable when extra width isn’t necessary. These are available in either solid or laminated forms and can include three- and four-plate designs.

T-style insert molds maximize the usable mold area and are available in laminated forms with three- and four-plate designs. Smaller sizes can be made in either solid or laminated styles.

How We Works

Get Your Request

Get your detailed requirements for injection mold manufacturing, including mold materials, mold life, number of mold cavities, runner requirements, and surface treatment requirements

Confirm DFM Report

Our engineering team begins to conduct mold flow analysis and provides DFM ( Design for Manufacturing) report according to your detailed requirements and confirms all details with you

Mold Deisgn

Our engineering team make a 3D drawing design of the injection mold based on the confirmed DFM report, including all details of the mold and confirm the mold design drawings with you

Mold Final Acceptance

After the final sample is confirmed, we start the final acceptance of the injection mold. If it is an export mold, we need to do the final injection mold packaging. If the mold is ready for mass production in our factory, we prepare the production materials.

Mold Assembly & Testing

After the injection mold is made, we start fitting the injection mold, assembling the injection mold and testing the injection mold. We repeat this work until the product is tested and meets your requirements, and then we send you some samples for confirmation.

Injection Mold Manufacturing

Based on the confirmed mold drawings, export the 2D drawings with the key dimensions and tolerance requirements, and then our plastic injection mold makers start injection mold manufacturing and tolerance inspection of each processing step

Why Choose Zetar

Zetar stands out as a premier, all-inclusive injection mold inc, having consistently achieved the ISO 9001, ISO 13485, ISO 14001, and ISO 45001 certifications, demonstrating our commitment to top-tier quality, health, environmental, and safety standards. Since our inception in 2005, our focus has been on manufacturing plastic injection molds. 


MUD Injection Mold Solutions

Discover the Ideal Injection Mold Solutions for Your Injection Molding Project: Achieve Excellence with Optimal Solutions

Everything You Need to Know About MUD Injection Mold

What Is MUD In Injection Molding?

Master Unit Die (MUD) injection molding is a versatile and efficient solution for manufacturing processes that need quick mold changes. It’s known for reducing downtime and increasing productivity in plastic injection molding.

In injection molding, “MUD” refers to Master Unit Die. This system streamlines and economizes the molding process, especially for small to medium production runs. The MUD system includes a universal frame that fits into an injection molding press. Within this frame, interchangeable insert molds can be quickly swapped.

This modular design enables easy changes to the mold inserts without replacing the entire mold, reducing downtime and enhancing production flexibility. The inserts contain essential components such as ejector plates, core pins, and mold cavities. This system is ideal for producing multiple parts simultaneously and is valued for its cost-effectiveness and efficiency in mold setup and changeover times.

What Is MUD Mold?

A MUD mold, or Master Unit Die, is an injection mold suited for small to medium production runs. It includes a unit die with multiple cavities, facilitating the simultaneous production of several parts. The MUD system is modular, with a standard frame and interchangeable insert plates that enable quick production process changes without requiring a full-sized mold clamped to the press.

What Is the MUD Quick-Change Concept?

How can MUD make injection molding more affordable?

The Master Unit Die Quick-Change Concept was developed to address the dual challenges of boosting productivity and cutting costs. MUD Quick-Change Systems are increasingly integrated into the operational frameworks of numerous companies that embrace lean manufacturing programs, as they have demonstrated the ability to enhance uptime and lower expenses.

The tooling strategy for injection molding provides mold makers and plastics manufacturers with several competitive benefits. These encompass reduced tooling expenses and quicker production changeovers. The notable flexibility inherent in this approach makes it well-suited for just-in-time scheduling.

How can reduced tooling costs improve overall production efficiency?

The Master Unit Die Quick-Change system is founded on the concept of an infinite array of companion insert molds that can be effortlessly swapped within a single MUD Quick-Change frame, which remains within the molding machine during mold transitions.

Most changeovers are completed in under five minutes and necessitate no special tools, being executable by a single operator. Simply loosen four clamps, disconnect any heating or cooling lines, slide out the insert mold from the Quick-Change frame, insert the replacement, reconnect the lines, and clamp back into place. The newly inserted mold is now primed for production.

This tooling methodology slashes downtime by up to 75 percent. Additionally, associated labor costs are further diminished as the assistance of a second person during mold changes becomes unnecessary.

The upfront investment in new tooling is reduced by as much as 70 percent. This is attributed to only replacing the companion insert mold to manufacture a new part, instead of replacing an entire standard mold base. Labor costs are also curtailed as insert molds are more manageable than larger, weightier standard mold bases.

This amalgamation of decreased production downtime, lower labor expenses, and diminished tooling outlay can translate into a notable surge in profit margins.

Quick-Change Frames and Companion Insert Molds

What is MUD Injection Mold Frame?

The MUD Quick-Change Concept comes in three frame series and in sizes for the smallest air-operated machines to models for 500-ton machines.

The MUD U frame series offers the most design flexibility and accepts both standard and T-style companion insert molds.H frame and Double H frame models offer simultaneous molding with two and four standard style companion insert molds. The benefits of both Quick-Change tooling and hot runner molding can be combined with the addition of a manifold to MUD H and Double H frame models.

All Quick-Change frames are precision made to exacting tolerances and are easily matched to the specifications of individual machines. Each is engineered for extra strength and rigidity and is designed for maximum molding flexibility.

What Is MUD Injection Mold Insert?

Master Unit Die companion insert molds for Quick-Change frames give designers and mold makers exceptional application flexibility. Each is available in a variety of steels and is interchangeable within matching frames. The insert mold includes the cavity and core plates with leader pins and bushings installed and the ejector plates. Since this insert assembly is all that’s needed to produce new parts, tooling costs are reduced significantly.

Standard Style Insert

Standard Style Insert Molds offer maximum economy and come in solid or laminated construction including three- and four-plate designs. Options and features include stripper plate, sleeve ejection and other special applications designed to meet virtually all injection molding needs. See U frame, H frame and Double H frame sections for details.

T-Style Insert

T-Style Insert Molds offer the maximum projected mold area and come in laminated construction including three- and four-plate designs. Smaller models are also available in solid construction. Options and features include stripper plates, sleeve ejection and other special applications. See U frame section for details.

What Are the Advantages of Using MUD Injection Molds?

Quick-Change tooling offers you advantages at every step in the manufacturing process — from tooling lead time and cost to production and inventory control.

Faster Delivery

You’ll get your new tooling orders faster because you only need a companion insert mold, not a whole standard mold base. That means less machining time. And chances are the insert mold you need is in stock and takes no more than seven to ten working days to ship.

Lower Mold Costs

You save plenty! Tooling expense is cut substantially with the new job, without recurring tooling expense, which is reduced as much as 70% or more! Also, the MUD Quick-Change Frame cuts recurring tool costs with the use of spacer bars! In the bigger frames, this lets you use smaller and less expensive insert molds!

Mold Setup Simplified

Setup’s a cinch. The MUD Quick-Change Frame stays in the molding machine. All you do is slide in the insert, clamp it in, hook up your heating or cooling lines, and you’re ready to go!

Maximum Volume Production

When it comes to high-volume production, H Frames and Double H Frames really take over. You can double (H Frame) or quadruple (Double H Frame) the quantities that come out with each cycle when you’ve got multiple insert molds. You’re ready for scheduled maintenance, too! Because you can interchange insert molds so rapidly, you can put backup inserts in while you work and keep the line running until later when you shut it down.

Changeover Quick

Stop the machine. Loosen just four clamp bolts, unhook the heating or cooling lines, and slide your old insert out of the way. Slide in your new one, hook up the lines, clamp it in, and start running again! Most changeovers take less than five minutes.

Minimum Purging

Super-fast changeover of MUD inserts means you will rarely have a machine cylinder to require purging due to overheating. And that saves you both raw material and open time.

Easier Maintenance and Repair

You’ll find it much faster to remove and re-install MUD inserts than standard mold bases. Plus, they’re much lighter and smaller. This means scheduled preventive maintenance is a snap. And downtime is cut way down if an insert has to come out for modification or repair. Even if an insert will be out for a long period, a replacement can be quickly installed and you’ll be back in full production in less than five minutes.

Convenient Storage

Since the MUD Quick-Change Frame stays in the machine, only the companion insert mold has to be stored. And it’s easy to handle because it’s so light and small. Most models can be stored on your bookcase type shelves.

Flexibility In Production

The MUD Quick-Change H and Double H Frames are built for multiple insert molds to run at the same time. These molds can be changed out one at a time. When you're only going to be running with one insert mold, just put a dummy insert in the chamber. When the job is bigger, double up by putting in duplicates.

Creates Freedom in Design

MUD companion inserts come in T pattern or standard pattern construction and in either solid or laminated design. That gets you all the design options you’ll ever need. You can make these inserts handle parts with stripper plates, sleeve ejection, single- or double-cam action, hydraulic cylinders, mechanical cylinders, air cylinders, and all the other goodies. You can even use three or four plates with them.

What Are the Applications of MUD Molds?

Prototypes and Samples

The MUD Quick-Change system is ideally suited for this type of application
because the setup and startup are so quick. Even more important, engineering
changes affect only the companion insert mold, not an entire standard mold
base. This keeps the time and cost for sample and experimental tooling to a

Short Production Runs

When you have to make a bunch of different parts in a short amount of time, the MUD insert molds are just the thing you need. Besides going like hell from one part to the next, you’ll probably save the need for any overtime by getting lots of stuff done in just a few hours. Something else you’ll like about these insert molds is that they’re so cheap you can have duplicates. And when you absolutely, positively have to deliver by Friday, this is good insurance.

High Volume Production

One of the big things that makes you fast with Quick-Change is you get to make more than one part at a time. Besides getting more parts per hour or day, you save money because you don’t need all the duplicate molds. You’ll like that you can change molds so fast without it costing you time and money. You’ll also like that you’ll have more time to fix the molds because it takes less time to take them apart and less time to put them together. MUD Quick-Change stuff can handle the demands you get in high volume production because it’s made to keep on keeping on.

Aluminum Insert Molds

The thermal conductivity of aluminum inserts is about four times greater than
that of steel, which keeps the mold cool so that you can cycle the molding
press faster. The lightweight of the inserts makes them easy to handle and
they can be machined at high speeds.

What are The Steps Involved in Changing Cold Runner MUD Injection Mold Inserts?

Swapping out the inserts on a cold runner MUD (Master Unit Die) injection mold requires a series of steps that are designed to ensure that the process is efficient and safe. Here are the steps to changing the MUD inserts:

Step 1: Mold Open

Step 2: Mold Open, Release The Insert Clamps

Step 3: Mold Open, The Inserts Replaced With New Inserts

Step 6: Mold Closed

Step 5: Mold Open, New Inserts Secured By Clamps

Step 4: Mold Open, The New Inserts Lowered Into The Frame

What are The Steps Involved in Changing Hot Runner MUD Injection Mold Inserts?

Hot runners can also use MUD quick change systems.This procedure is a general guide and specific steps for hot runner MUD injection molds.

Step 1: Mold Open

Step 2:Mold Colsed

Step 3: Mold Colsed, Attach A &B Inserts Together at Parting Line

Step 6: Mold Open, Release The Insert Clamps

Step 5: Mold Open, B Side Pulls The Frame & A Insert Off Guide Pin

Step 4: Mold Closed, Detach The Frame From Hot Half

Step 7: Mold Open, The Inserts Replaced With New Inserts

Step 8: Mold Open, The New Inserts Lowered Into The Frame

Step 9: Mold Open, New Inserts Secured By Clamps

Step 12: Mold Closed, Detach A &B Insert At Parting Line

Step 11: Mold Closed, The Frame Is Attached To Hot Half

Step 10: Mold Closed

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