- Plastic Injection Mold Design Basics
- Plastic Injection Mold Design Basics
- Building a Plastic Injection Mold - Lesson 1 of 10 Mold Making Basics
- The Basic Plastic Injection Molding Process
- Injection Molding
Plastic Injection Mold Design BasicsThe first step is to create a mockup of the part. Most projects start with an idea or a sketch. Then, the blow molding design team creates a three-dimensional CAD or e-drawing of the part. A high-quality blow mold is the foundation of manufacturing your blow molded part. Your team will review mold design details to ensure ease and efficiency in production:. You will also review the blow molding design before the mold is put into production. This will ensure your product vision is aligned with the production process. Once the mold is designed, built, and approved, your product goes to production. Throughout the process, your blow molding team will conduct regular, intensive quality checks to ensure smooth sailing. A good blow molding supply team is dedicated to getting every piece right for you, the first time around. Interested on how your design team enhances your product? Check out our blog on how your blow molding supplier optimizes your product design. At Custom-Pak we are always happy to answer your questions. Please let us know how we can help you. Call or contact us today! Create a mockup of the part. The e-drawing allows you to: Visualize your part accurately before your supplier creates a physical model or mold. Rotate and measure a virtual model of your part to determine the initial dimensional expectations. Make modifications to suit your design preferences. Address functionality and structural issues right out of the gate. Develop cost estimates for the part and the mold based on the material, quantity, quality, and timing desired. Verify the product meets your stated commercial goals, from functionality to aesthetics, to optimize the potential for market success. Design and build the mold.
Plastic Injection Mold Design Basics
Basics: One of the most important parts of building a mold that is capable of making millions of part, is the mold design. In this instructable we will take look at the pig picture when designing and building molds. We will break down 10 future lessons into the following lessons. Plastics are essentially squeezed into a chamber with a machine that takes small pellets and melts them before it is pushed into the cavity. Cooling is routed thru the mold to make the process run super fast. If you find that you need lots of parts, you can add multiple cavities or a pattern of cavities. One can imaging when plastic molecules are cooling, then tend to shrink from a liquid state to a solid state. Molds must accommodate for these changes, so the cavities and cores are scaled up so the plastic will shrink back to size. We will refer to this subject as shrinkage. These cavities and cores are mounted in a mold base where small pins are used to knock the plastic parts out of a cavity or core. The core is traditionally on the "B" side of the mold. This is also refereed to as the ejector side of the mold. The cavity is on the "A" side of the mold or the hot side. That is the fixed and stationary in the molding machine when it is bolted down. We traditionally inject the plastic into this "A" side of the mold. Did you use this instructable in your classroom? Add a Teacher Note to share how you incorporated it into your lesson. Here is an 16 cavity mold starting up. This mold will make 3. We need to first understand how many parts are needed then we can figure out how many cavities and how big the mold and the molding press will need to be to satisfy those requirements. When CAMing in Fusion you need to start with large cutters, then work towards small cutters. It is important to not skip a step, or you will start breaking cutters. Remember, the deeper you cut with the smallest cutter it tends to break. So try to design your parts with the biggest radi in each corner. I'm interested to see how in depth you go with the tutorial. It could be a great way to introduce people to how much work it actually takes to make their polymer widgets. I'm also interested in what perspective you will be designing from i. One thing i would like to point out though; it is a common misconception about needing cold slugs at the end of each runner branch. Polymers exhibit "fountain-like" flow behavior during injection, in which the flow front is pushed out against the walls as new material flows in through the center. The only time a cold slug is actually pushed in front of the material is upon exiting the nozzle.
Building a Plastic Injection Mold - Lesson 1 of 10 Mold Making Basics
The various stages of the injection molding process are carefully considered when analyzing part design, tool creation and efficient production of molded plastic products. The heated plastic is injected into the mold. As the melt enters the mold, the displaced air escapes through vents in the injection pins and along the parting line. Runner, gate and vent design are important to insure the mold is properly filled. Once the mold is filled the part is allowed to cool for the exact amount of time needed to harden the material. Cooling time is dependent on the type of resin used and the thickness of the part. Each mold is designed with internal cooling or heating lines where water is cycled through the mold to maintain a constant temperature. While the part cools, the barrel screw retracts and draws new plastic resin into the barrel from the material hopper. The heater bands maintain the needed barrel temperature for the type of resin being used. Periodically the machine operators, or robots separate the usable parts from the left over runner. In many cases the runners are ground and recycled to reduce costs and environmental impact. The usable parts are then weighed, counted and packaged for assembly or shipping. Any unfamiliar terms used in this article can be found in the Aire Plastics Injection Molding Glossary of Terms online at:. So there you have it, the basic Injection Molding Process. Everyday we work with customers to help them understand the basic process that we are going through to produce quality products. Keeping you, the customer up to date and informed about the basics of how the injection molding process works will help you communicate with your molder. It will also help you understand and troubleshoot any problems he may be dealing with when molding your products. Injection molding is advantageous over other processes because of the precision and high speed at which products can be made. No other process to date can meet the quality and consistency of this process when molding plastic. If you have any questions please feel free to contact us at contact aireplastics. First Name. Last Name. Sign Up and Download. Step 2 of the Injection Molding Process. Step 3 of the Injection Molding Process. Step 4 of the Injection Molding Process. Step 5 of the Injection Molding Process. Step 6 of the Injection Molding Process.
The Basic Plastic Injection Molding Process
In mold design, note the following points, some of which also apply to product design. The processing accuracy of a mold must be within one-third of the tolerances. Stricter tolerances will present problems that the cost of the mold will be higher. Keep in mind that metal and resin differ in various aspects. If you have any similar products, refer to their trial results. If you do not have any molding examples available, it is necessary to examine the flow distance from a product drawing and set the basic wall thickness, sprues, runners, gate shape or the number of gates, and so on from the material fluidity data in Section 2. After the completion of the mold, check it by performing a trial and modify it, if necessary. The provision of ribs to compensate for the fluidity is also effective. If a gate is too small, the resistance at the gate will be high, which may result in defects due to increases in the shear heating of the resin, as well as problems sink marks and voids attributable to reductions in the gate seal time and so on. Depending on the wall thickness of the molded product, it is considered preferable for the gate diameter be at least 0. For a multi-cavity mold, use CAE analysis and so on to optimize the mold, ensuring that the runner lengths flow distances are equal, so that each cavity is filled with molten resin from the sprue at as close to the same time as possible. It is preferable to create a layout that is well-balanced on the whole by considering the parting line PL and the slide core structure. At a thick wall portion of a molded product, the resin is cooled quickly, so that the melt viscosity increases. Thus, if a gate is provided at a thin wall portion, the result will be insufficient fluidity. Also, solidification starts with the thin wall portion of the molded product, so that a sufficient holding pressure cannot be obtained, resulting in sink marks and voids in the thick wall portions. Near a gate, appearance defects such as silver streaks are likely to occur, and the flow pattern is likely to be turbulent. Thus, for glass fiber reinforced grades, for example, the portion near the gate may be more fragile than other portions. Also, excess molding pressure is applied to the gate, so that the residual strain may be large. Residual strain will result in poorer mechanical properties and so on. Thus, avoid providing a gate at any portion to which the principal stress carried by the product is applied. At an opening of a molded product and for a multipoint gate, welds may occur. For details, refer to Mechanical properties in the technical document. Welds are more fragile than non-welds. Thus, provide a gate in such a way that welds are not formed at a portion to which the principal stress of the product is applied. For a standard side gate, for example, appearance defects like resin flow patterns, resembling a slithering snake jettingmay occur immediately after the gate if, for example, the slug well in the runner is insufficient. To prevent jetting, provide a gate position in such a way that the flow direction of the molten resin changes immediately after the gate the resin becomes turbulent. From the perspective of productivity, it is preferable to provide a gate at a portion at which gate cutting is facilitated.