Category Archives: injection mold design

Mold Design Consideration for Automated Molding

Injection molders today are using sophisticated, automated equipment aimed at molding high quality products with lean processes.  Automated auxiliary equipment is used to provide consistency in a process while reducing cycle times.  Each injection molder’s shop environment is different, and some equipment must be custom designed to work together.

 

An injection mold designer must be aware of the molding environment in which the mold will run, which includes the type of press, any auxiliary equipment used in the molding process and the location of tie bars and cooling lines.  This information is vital to a proper mold design to ensure that nothing will interfere with installation or operation of the mold.

Some Automated equipment that injection molders use are vacuum conveying systems, sprue pickers, robotic arms and conveyors, computerized quality inspection and rejection procedures, and automated packing procedures.

As any molder knows, reducing cycle time provides cost saving efficiencies that equate to increased profits to the bottom line.  Be sure to share with your mold designer any custom design requirements unique to your molding situation.  

Michiana Global Mold is experienced with the most challenging of mold designs requiring tight geometric tolerances with critical dimensions.  We construct molds used for any environment, with custom designed solutions provided with Unigraphics CAD/CAM Software, and Mold Flow Analysis if required.  

We are an ISO Registered mold making facility following a strict quality policy in all aspects of injection mold design and construction.  Michiana Global Mold has been a valuable supplier to many supply chains including to the Automotive industry for over 50 years.  We employ a highly knowledgeable and experienced staff, with skilled designers and journeyman mold makers.

Michiana Global Mold has in-depth knowledge designing and manufacturing injection molds that meet tight geometric tolerances.  Contact us today for a FREE design consultation and to learn how we can assist with all of your injection mold requirements.  

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Injection Mold Design for Engineering Resins

Thermoplastic engineering resins are the most common type of plastic resins used in the injection molding process.  With many different types of plastic resins each with their own unique properties, it takes great care and consideration to properly design and construct a mold for use with thermoplastic resins.   These highly useful polymer resins have varying properties of elasticity, resistance to temperature, corrosives, shrinkage and right down to the exterior finish such as a matte or a glossy finish.  

Shrink rate is a very important property of thermoplastic engineering resins used in injection molding, as the cavities must be carved out to accommodate to this shrink rate.  If shrink rate is not accounted for properly, a part may shrink too much after cooling and deviate from customer requirements. Knowing the cooling and shrink rate of the polymer resin used for any molding process is of the utmost important to the journeymen mold makers constructing the tool.  

Cooling rate is also important for the part to become completely solidified prior to ejection.  Cooling rate must be configured into the injection molding cycle time, to ensure proper cooling and ejection without damaging the part.  

Each polymer resin will have a MSD sheet, Material Safety Data sheet along with material specifications clearly defined in each numbered lot of all thermoplastic resins.  If working with a new material, a mold designer may prefer to use Mold Flow Analysis, for a computer simulated demonstration of how the plastic material will melt, flow and fill.   Predicting the flow of thermoplastic resins prior to cutting steel is vital for accurate geometrical tolerances in the final product.  

Even with a material spec sheet which is necessary, nothing helps a skilled mold designer more than experience.  Skilled mold design engineers are very familiar with the various properties of engineering resins allowing for precise mold construction with even the most specialty of molding resins.  

Michiana Global Mold is an experienced mold design and construction company, with vast experience with various thermoplastic resins used in injection molding.  We employ highly skilled journeymen mold makers and expert design engineers to satisfy even the most demanding of customer requirements.  We tackle the complex mold designs that other companies shy away from.  For complex, precision molds that must meet tight tolerances, contact Michiana Global Mold today for superior mold design and mold making services.

Contact Michiana Global Mold today to speak with one of our skilled mold designers and learn how we can assist you with your next injection mold making project.  We are an ISO9001:2015 Registered mold making company with vast experience constructing custom, precision injection molds using various thermoplastic engineering resins.  

Plastic Injection Part Design with Ribs and Bosses

Ribs are often used to add strength and stiffness to plastic parts in critical areas or geometric designs where thin walls exist.  This makes the part stronger with added support but can also cause sink marks on the exterior side of the part, where the rib comes together to meet the main wall in the part design.  When using ribs to add support, remember the general rule that the rib should not be more than 60% of the wall thickness.  Adding ribs to an injection mold design will increase costs, and may require EDM processes.  

 

Working with an experienced injection mold manufacturer will give you the best value for your investment.  Skilled journeyman mold makers and experienced injection mold design engineers will have the best knowledge of where to place ribs for added support and how this will affect the tool design, and the cost.

 

Mold making companies today can provide you with a two-dimensional computer aided design to show you exactly how your injection mold will produce the required plastic part, and alert you to any problematic areas ahead of time.  

 

Bosses are a very common feature in many plastic parts, and comes from the word emboss, which means a raised stamp or design, standing out on the surface.   Bosses that are designed with too thick dimensions can cause sink marks similar to the use of ribs.  Utilizing the proper ratio of ribs to bosses a molder can reduce or eliminate unsightly sink marks caused by either feature.  

 

Ribs used to connect boss areas to a side wall can add strength while avoiding sink marks.  Sharp corners are another area where excessive stress can concentrate and adding small radii feature in this area can strengthen the corner and reduce excessive stress.

 

Michiana Global Mold is a full-service mold design and construction company, with vast experience in all types of molds.  We offer an ISO registered Quality System, state-of-the-art domestic mold building facility with off-shore partner, and decades of experience with precision, complex tooling.  Contact us today for a FREE design consultation and to speak with one of our highly skilled design engineers.

Determine Proper Ejection Method for Injection Mold Design

Injection mold design includes design of the optimum ejection system to meet part specification.  While ejector pins are most commonly used, there are other methods of ejection systems that are required in specific situations.

Ejector pins are round, and used to extend into the cavity to push the part out during mold opening so that the parts fall out or are pulled out by a robot.  Pins are adequate in most situations, although some part designs require pins along with an alternative method, or a different method altogether.

 

Ejector blades can also be used for ejection if the part design requires it, and these have more of a rectangular geometry.  Ejector blades are often used in designs where a thin wall exists, thus an ejector pin may damage the part with force or pressure applied in a critical area.

 

Ejection sleeves are tubular, and are ideal in areas of raised surfaces.  These raised surfaces are designed to assist with assembly in some designs, for example a raised hole at the end of a vertical part would be referred to as a boss.  Ejection sleeves provide 360° surface around the boss for easy part ejection with these types of part designs.

 

A stripper plate is another type of ejection system that consists of an entirely separate moving plate, that is designed to strip the part or parts from the core of the mold.  These are ideal in situations where you need to keep parts and runners separate, and are utilized in three-plate tool.  

 

Michiana Global Mold is a leading global injection mold design and construction company, with extensive experience in all types of ejection systems.  Our skilled mold designers and journeyman mold makers have extensive knowledge and experience with various types of mold construction.  We construct prototype molds with sample parts, cold runner or hot runner tools, shuttle molds, insert cavities and all aspects of injection mold design including engineering changes.

 

Michiana Global Mold was established in Indiana in 1964, serving various industries and specializing in complex, precision tools for the Automotive industry.  We offer a partner company in China with offshore mold making capabilities.  Both facilities are registered to ISO 9001 and follow strict quality management systems.  Contact us today for a FREE design consultation and to speak with a skilled design engineer.  

Precision Molds for Complex Part Designs

Injection mold designers must use careful consideration when designing a mold for a complex part design.   Intricate plastic injection molded parts may contain several critical areas that must be carefully designed to meet part specifications.  Parts that contain a very thin wall, for example, would be a critical fill area.  It takes expertise in mold design to fill a part completely without any overfill or underfill while still maintaining the integrity of such a thin critical dimension.

Critical areas should be identified on the part print, and throughout the entire mold design phase.  Sophisticated CAD/CAM software is used to develop a viable tool design given all part design specifications and other exterior design considerations such as the specified material and press size.  With a superior design software program like Unigraphics or SolidWorks, mold designers can develop the entire mold construction phase and test critical areas with computer simulation software.  This advanced quality planning phase is crucial to constructing precision molds to customer specification, and within the established lead time.

The part print will also contain specific information such as the resin used and the surface finish or texture required of the final part.  Any restrictions on knit or parting lines must be identified for proper gating.   It takes an experienced mold designer to implement a successful tool design and construction of a precision mold for injection molded parts with a complex design.

Download our FREE Book on Design Considerations for Different Molds, and contact us today to learn about our discount and rebate programs.  

Michiana Global Mold is an experienced injection mold design and construction company, supplying precision tools to various industries since 1964.  We are an ISO registered mold shop, satisfying the strict requirements of the Automotive industry with high quality complex molds.  Contact us today to speak with one of our knowledgeable engineers for a FREE design consultation.  

Mold Design and Automated Injection Molding

When an injection mold designer begins a development of the mold design, they must be aware of the environment in which the mold will run.  This includes the size and type of press the mold will run in, the material used for molding, and any auxiliary equipment used for automation as the location of tie bars and cooling lines must not interfere with setting and running the mold.

 

Vacuum Conveying System

 

A vacuum conveying system is an automated way to get the material into the press, with the right suction and force.  Vacuum conveying systems suck the material while still in pellet from the gaylord or drum into the hopper of the press, providing a steady flow of material for continuous production.   Vacuum conveying systems pull in a steady flow of material, and control the amount of material in flow to the press, and are also helpful with controlling the moisture content in the material.  

 

Sprue Pickers Aid Automation

 

Sprue pickers are robotic arms that reach into the press and grab the runner when the mold ejects, instantly separating from it the parts which can then fall into a bucket or onto a conveyor belt.  Some robotic sprue pickers reach in and pick up the runner then drop it either into a separate bin, or directly into a grinder where it can be ground up and reused as regrind material.  

 

Process Monitoring

 

Injection molders use process monitoring systems to constantly monitor the press settings such as temperature and pressure, alerting an operator if the job begins to run out of specification.  Some monitoring systems also provide material resource planning functions, tracking job due dates and material inventory for scheduling of jobs.  

 

All of the additional auxiliary equipment must function properly and work in conjunction with the mold when it opens and closes and operates on the tie bar.

 

Michiana Global Mold has vast experience designing and manufacturing molds adhering to customer specifications and each unique environment.  Contact us today for a FREE design consultation and to learn how we can assist.  

Mold Design Considerations for Thermoplastic Resins

The most common type of polymer used in injection molding is thermoplastic resins.  There are many different types of resins with various properties to meet part specifications for functionality.  When designing injection molds, the engineer must take into consideration all properties of the resin specified for the produce including adhesion, elasticity, resistance to high temperatures, shrink rate, resistance to corrosives, and desired finish whether matte or polished.

 

The cooling and shrink rate are of the utmost importance, as some parts with a high shrink rate will need the cavity designed accordingly so the finished product will cool and shrink within specifications.  Cooling rate is also important for ejection, as the resin must completely solidify prior to mold ejection.

When an injection molded part has a critical functionality, mold flow analysis may be helpful in determining resin flow into tight geometric areas.  Mold flow analysis clearly shows with computer aided simulation how the resin will flow as determined from its properties.  Predicting how thermoplastic resin will flow in the mold and cavities prior to cutting steel can be a valuable tool in avoiding costly mistakes.  Conducting the proper advanced quality planning with mold flow analysis can greatly improve lead times.  

Most journeyman mold makers will already possess the knowledge of hos particular resins flow just from experience.  A skilled design engineer with experience in manufacturing molds will have the knowledge to design the tool to produce a part to print specifications, with the chosen resin properties playing a huge role in tool design.

At Michiana Global Mold, we have been providing high quality precision molds for over 60 years, possessing more than 500 years of combined experience.  Our staff of highly skilled design engineers and journeymen mold makers are the best in the business with vast experience in various thermoplastic resins.

Contact Michiana Global Mold today to speak with one of our skilled and experienced mold designers to learn how we can assist you with your injection mold requirement.  We are an ISO9001:2015 Registered mold making company with vast experience constructing custom, precision injection molds for various industries.