How to control the cost of plastic injection molding?

The cost control of plastic injection molding also involves many factors. It must be controlled from the equipment, application process, raw material, as well as management and technology to achieve the optimal efficiency at the lowest cost.

Plastic injection molding company from China

Tools and Components Control:

Tools – All screws, nuts, nylon hoses and hose clamps, etc. in the packaging workshop must be controlled with a corresponding method, or great waste will be caused!


Mold Application Control:

Production Process:

  • Appropriate clamping pressure during the adjustment process – It is appropriate as long as the product meets the requirements, and the clamping force is able to ensure that the injection pressure does not force the core and the cavity open to cause flashing.
  • The ejection speed needs to be properly controlled. The ejection system itself is a system that should avoid as much friction as possible. If the speed is too fast, the system will inevitably be damaged.
  • Make full use of the low-pressure protection feature of the injection molding machine, so that there is chance for the mold to be damaged.
  • Too-high or uncontrolled injection pressure, speed, holding pressure and back pressure are also important factors that cause damage to the mold or affect its service life!
  • Mold temperature control is also very important. Excessive mold temperature will cause the individual parts inside the mold to swell and the compatible space to change, thus finally damaging the mold. The too-low mold temperature is not able to ensure the mold temperature to reach a relative balance after the mold absorbs the heat generated by the melting of the plastic, thus eventually causing rust and damage due to long-term moisture in local areas!
  • Human factors: Especially when such issues as mold adhesion or scratches and other common mold issues occur, a specialist is required to handle them. Do not arbitrarily authorize anyone to handle them casually.

Maintenance & Storage:

  • During the production process, the moving parts such as the lifter, the side pin, the slider, the guide pin and the ejector pin must be thoroughly lubricated at least once a day, or more than twice a day in special circumstances.
  • During hot-oil production, it is necessary to pay attention to the clamping of the mold and the partial swelling of the slider. During cold-water or icy-water production, the coolant must be cut off at least 15 minutes before shutting down the machine!
  • Pay special attention to the matte-surfaced mold and the polished mold – don’t damage or scratch them, or it will be quite troublesome to repair them!


Application of the Injection Molding Machine:

Plastic Injection Options:

  • Injection Volume:During the production process, the choice of injection molding machine is usually to ensure the molding quality. The weight of the product should be 25-75% of the total weight of the injected plastic, which is the recommended ratio. If the best product volume is required, the range should be lowered to 40- 60%.
  • Wear- / Corrosion-resistant Barrels and Screws:If the glassfiber-reinforced hard plastic is selected, it is better to choose wear- / corrosion-resistant alloy barrels and screws. Wear tends to occur when common nitrided screws are employed: choose corrosion-resistant alloy screws and barrels for acidic materials, such as PVC and POM.

Cost Control during injection molding Machine Adjustment:

  • Reduce wear and tear:If abnormal wear and tear is caused due to improper operations or other accidents during the adjustment process, the machine will not be able to operate properly for 12 years. Eventually, the daily wear and tear will increase greatly, and at the same time lead to incalculable and serious maintenance costs! To reduce abnormal wear and tear, it is necessary to strengthen the technical level of the technicians, as well as the knowledge of other workers.
  • The choice for the switch point between injection and pressure holding is able to reflect the actual operation level of a technician in an injection molding workshop. When realizing that the most fundamental purpose of pressure holding is to compensate for the shrinkage, the injection time and pressure can be minimized to reduce wear and tear, as well as power consumption, thus finally achieving the requirements for cost control!
  • The mold opening and closing process also reflects the actual operation level of a technician in a plastic injection molding workshop, because it fully reflects the connection between speed, time and energy consumption!


Material Cost Control:

The key to the cost control of a plastic injection molding workshop is the material control. If material control fails to reach the target, it will directly lead to a serious decline in profit. Any carelessness may lead to loss of profit.

Starting from the plastic materials release, control every detail to ensure zero material waste.

  • The machine cleansing process: Firstly, the machine scheduler must schedule the production from light to deep colors, so that it is possible to eliminate the discoloration that may occur by using a deep color to cover a light color. When cleansing the machine, first try to cleanse the machine with prepared sprues or recycle materials, and then adjust the machine using the sprues of the material to be used. When the product reaches the required quality, the production officially starts.
  • Machine adjustment process: Try to use the parameters and instructions provided by the flowchart, making the adjustment process a process of copying the book or inputting the parameters, thus simplifying the general adjustment process.

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