Month: March 2018

automobile injection mold

What Is A Quality Injection Mould Maker

Klarm Mould

An injection mould maker is a machine for producing parts by injecting at high pressure, usually plastic material into a mould. The plastic used are thermoplastic and thermosetting polymers. Material for moulding is conveyed into a heated barrel where it is mixed and then injected into a mould cavity where it hardens by cooling into the shape of the mould. Mould may be made of steel, aluminium and are themselves made with extreme precision so that the desired parts are created to match the design. Vice versa, those parts are also designed so that they are well suited  for injection moulding. The adaptability of injection moulding lies in this breadth of design consideration and possibilities, of both the injection mould maker in China and the item to be moulded.

automobile injection mold
automobile injection mold

Injection moulding finds application in almost all manufactured items, from plastic bottles to car parts.

  • A quality injection mould maker (person) should support his customer right from the concept stage to the mass production stage. He should know what questions to ask and anticipate where he is going to face difficulties in the moulding process while the part is being designed
  • A quality injection mould maker should be complete and integrated and yet have a variety of systems for different applications.
  • It would by virtue of being a quality item, be assisted by robotic systems.
  • They should be environmentally friendly, and have energy and space saving features.
  • The manufacturers should offer technical support and systems for factory automation.
  • Water circuits in a mould maker should not be looped as this leads to warpage.
  • The quality injection mould maker (person) should be present at the design stage of the part to anticipate difficulties in mould making and design.
  • Use of 3D rapid prototyping from 3D computer models is useful in injection moulding eg. To design water cooling channels along the contour of the mould which improves the quality of the parts and improves cycle times.
  • An internal storage memory for 50 molds is available
  • Fault diagnosis with alarm messages is possible
  • The command control centre should be shielded against magnetic interference.
  • A weekly schedule should be incorporated.
  • A quality injection mould maker that is driven by an electric motor has the following advantages over a hydraulic moulding machine
  1. A significant energy reduction of 40% to 50% is possible by electric compared to a hydraulic injection mould
  2. Stabilization of the molding process is achieved by use of the servo motor in the injection process
  3. Noise generation level is much lower.
  4. Molding cycle can be shortened by using different motors for different stages of the moulding cycle and running them in parallel, like opening, closing, injection, ejection, and weighing
  5. Injection speed can be increased
  6. Since no oil is used, it is an environmentally cleaner process.
  7. A digital display is always welcome
  • They should be low maintenance
  • A two year warranty which covers the replacement and or repair of any part that has a manufacturing defect.

Injection mold makers in China are supplying plastic injection moulding machines all over the world, at very competitive rates. They are also setting up offices all over the world to serve their customers better.

Resource box: This article is originally posted from https://www.injectionmouldchina.com.

plastic injection molded parts

How To Make Precision Plastic Molded Parts

Klarm Mould

Precision Plastic molded parts can be made only by Plastic injection molding. This is the preferred method because injection molding has the advantages of high tolerance precision work.

The following points go into making Precision Plastic molds.

plastic injection molded parts
plastic injection molded parts
  1. Using the proper clamping force

Injection molding machine – also known as presses, consist of a material hopper, an injection ram or plunger, and a heating unit. Plastic is injected into the mold through the sprue orifice. These presses are rated by tonnage which is the calculation of the clamping force the press can exert. This force keeps the mold closed while the molding is going on. By rule of thumb, the force needed is determined by the projected surface area of the part being molded. Tonnage can vary from a few to a few thousand. The nature of the material also determines the clamping force. If the plastic is stiff, more injection pressure and more clamping force is needed to keep the mold closed.  Also, larger parts require greater clamping forces. These points should be kept in mind when molding.

  1. Using the proper material for Molds – or die refers to the tooling used to produce the plastic parts by molding. They are expensive to manufacture and were preferred to be used only in large scale production. They are typically constructed from hardened steel, beryllium-copper alloys or aluminum. Steel though expensive, is more long lasting and its high initial cost will definitely be offset by the number of times it can be used. Pre-hardened steel is used for larger parts molding. The mold is heat treated after machining for longer life.

Aluminum Injection Molds cost much less and are used for mass manufacture of small parts. Aircraft quality aluminum is used for making molds. They offer quicker turnaround times because of their high heat dissipation quality. Since they are not wear resistant, they can be coated with fiberglass reinforced material.

Beryllium Copper also is used for quick heat removal especially where the shear heat is more. Shear heat is the phenomenon of heat trapping in a viscous material like melted plastic when the mechanical energy of the plastic granules when they are injected under high pressure is converted to heat energy.

  1. Using the right Gate

The main enemy of injection molding is stress. The molecules of plastic undergo severe stresses as they are extruded out of the injector into the crevices and corners of the mold to take that shape. They are forced to take sharp corners instead of their natural flow movement. These stresses when the part is cooled get locked into the part and cause warping, cracking, sink marks etc.

Gates are provided at the point of injection to prevent warping. Depending on the shape and size of the part, different types of gates are used.

  1. State of the art Machining

Using the proper machining to achieve very tight tolerances for their clients molded products. Proper initial designing is very important and can be outsourced to experts on a turnkey project basis. State of the art CNC machining, large boring mills, Blanchard grinding capabilities, conventional EDMs all go into making that perfect precision plastic mold.

Mold manufacturers in China have incorporated these and many more features to produce high quality Chinese molds that are in demand the world over at a fraction of the cost at which they are available in western countries.

For more information, please check out https://www.injectionmouldchina.com.