Thermo Plastic Into A Mold Cavity example essay topic

Wilbert Plastic Services Auburndale, FL 202 Progress Road Auburndale FL 33823863-967-6604 Fax: 863-967-1254 In the early days manufacturers came to us for a specific thermo formed or injection molded part or parts for a product they were making. Over the years we noticed that, more and more, they were coming to us for entire sub assemblies and more complex parts that might incorporate both thermo formed and injection molded parts. Based on that experience, and our knowledge of the pressures that manufacturers are under to increase efficiency and reduce cost, it became obvious to us that we needed to provide a wider array of services to help our customers increase their efficiencies, reduce their overall costs and maximize their ROI on each project, part or component. This vision has lead us to add assembly, decorating (in and post mold), reusable packaging, RFID and much more to our capabilities.

We believe that Lower Overall Customer Cost comes from an innovative, total solution made up of customer focused, operational excellence. By combining quality production and secondary services with design expertise, supply chain management, and world class logistics WPS has been able to help our customers find new ways to lower their costs and improve profitability. Injection Molding is the process of forcing melted thermo plastic into a mold cavity. Once the plastic has cooled, the part can be ejected. The first injection molding machines were built in the 1930's.

There are six major steps in the injection molding process: Clamping An injection molding machine consists of three basic parts; the mold, the clamping unit, and the injection unit or units. The clamping unit holds the halves of the mold under pressure during the injection and cooling. Injection During the injection phase, plastic material, usually in the form of pellets, are pulled from a hopper on top of the injection unit. The pellets feed into the cylinder where they are heated until they reach molten form. Within the heating cylinder there is a motorized screw that mixes the molten pellets and forces them to the end of the cylinder. Once enough material has accumulated in front of the screw, the injection process begins.

The molten plastic is inserted into the mold through a sprue, while the pressure and speed are controlled by the screw or in some cases a ram. Dwelling The dwelling phase consists of a pause in the injection process. The molten plastic has been injected into the mold and the pressure is applied to make sure all mold cavities are filled. Cooling The plastic cools to its solid form within the mold. Mold Opening The clamping unit is released, which separates the halves of the mold. Ejection An ejection rod and plate eject the finished part from the mold.

Some Advantages of Injection Molding High production rates Repeatable high tolerances Wide range of materials can be used Low labor costs Minimal scrap losses Little need to finish parts after molding In-Mold Graphics Molding In-Mold Painting / Coating Wilbert Plastic Services has lead the way in the use of In-mold coatings - special paints sprayed onto the mold surfaces - as an alternative to post-mold painting. After application, these paints dry for a brief time so that the injection mixture flows over the semi-dry coating during mold filling. Typically In-Mold painting is used for large, relatively simple parts, without complex details. Other points to consider when selecting an in-mold coating include: In-Mold spraying is relatively straightforward and less labor intensive than post-painting.

In-Mold coating can reduce and, save the cost of, most secondary finishing steps. Perfect adhesion between the in-mold coating and the substrate is almost guaranteed. Because in-mold systems are low in solids they follow the contours of the mold design very well. Therefore, fine details in the mold will be faithfully reproduced.

Mold surfaces must be very high quality, as every detail is reproduced. In certain instances the presence of an in-mold coating can improve the flow characteristics of the thermo forming material resulting in fewer sub-skin defects. Paint usage is relatively low compared with post-painting. In Mold Decorating Colors, patterns, wood grains, brushed metal, or bright chrome, plastics in a variety of finishes including glossy, matte, or textured are coming out of molds with every kind of finish and feel. The use of for mable films is aiding manufacturers seeking lower-cost and environmentally friendly alternatives to paint and other secondary processes. Already well established in auto interior & exterior trim, and hand-held electronics markets, the appeal of In-Mold Decorating is making itself felt in many new areas.

For mable films are an economical, durable, and environmentally friendly means of producing fully decorated parts right out of the mold. In-mold decoration (IMD) with for mable film inserts is replacing traditional post-mold painting, printing, hot stamping, and chrome plating. The process achieved its first successes in modestly sized and relatively flat parts for interior and exterior automotive trim and cell phones. Today, IMD technology has progressed to larger 3 D parts such as entire instrument panels, bumpers, fascias, roofs, and even hoods for cars and trucks. IMD also boasts lower scrap rates, ability to mold and decorate in one location, and improved. IMD can achieve a Class A surface without the flow marks that can occur with molded-in color.

The IMD or film-insert decorating process starts with a thin plastic sheet that is printed, coated, or pigmented for decorative effect. It is die cut into a blank and thermo formed to the shape of the final part. After being trimmed, it is then placed in an injection cavity, where it is back-molded with a compatible substrate. The surface can be a solid color, metallic appearance, wood grain, symbols and / or graphics.

The leading edge of IMD development is in weather able Class A finish for exterior automotive and heavy truck applications. Of the six major suppliers of for mable films for IMD, five offer outdoor weather able products and the sixth is working on it. Structural Foam Molding Structural foam is created using a chemical additive that is mixed in to the base resin at a certain percentage or injecting a gas right in to the melt stream at the nozzle. In either case, the outcome is a cell like structure in the part that reduces part weight and material content and maintaining material properties. Long Glass Fiber MoldingWPS has proven experience in the handling, drying, and processing of LGF. The material experience includes processing of fiber lengths up to 11 mm.

There are several mistakes commonly made when processing LGF. WPS has specific knowledge about how to overcome these mistakes. Among the most common are material conveyance, clogging, loader size, filtering, injection unit sizing, wrong screw, nozzle configuration, gating, and flow paths in the mold. Additionally WPS has specific experience in the use of gas assist molding to enhance the surface finish with LGF. By fully exploiting the gas assist process WPS can influence the resin to the surface of the molding and therefore provide an excellent surface finish. WPS also has specific knowledge concerning the use of color with LGF.

Many of the normally used color concentrate systems cause undesirable effects with LGF. Certain color systems can reduce the normal strength of the LGF material by 75%Gas-Assist Molding The gas-assisted injection molding process is capable of producing hollow, lightweight, rigid parts that are free of sink marks and less likely to warp. Other advantages include: Reduced cycle time Reduced pressure and clamp force tonnage Part consolidation with both thick and thin sections Insert MoldingWPS has proven experience in the automated handling of metal to achieve insert-molded articles. Typically, a metal insert is pre-positioned into a nest with a programmable robot, then a second robot moves the oriented insert into the mold and is positioned with mechanical holders or magnets. After mold closing, the plastic is injected onto the metal substrate to achieve the desired result. Alternatively, inserts can be placed into the mold by hand with magnets or friction fits.

These techniques allow one to eliminate secondary assembly and reduce components in a given assembly. Twin-Shot MoldingTwinshot molding is the process of molding two different materials at the same time. One material makes up the inner section of the part and the other makes up the external portion of the finished part. The two materials use the same barrel. Co-Injection Molding is similar to twin shot molding but it uses separate barrels. OvermoldingPlastic-on-plastic 'insert molding' (Over molding) can be accomplished by combining different plastics to achieve desired results.

For example, a softer duro meter material may be over molded onto a structural core material. This can be accomplished several ways. Placing a previously molded article into a mold and then 'over molding' another material onto the base article can achieve unique results. The same results can also be accomplished through gas counter-pressure. By maintaining a cavity pressure, which resists the plastic pressure inside the mold, you can achieve the same result as above without a subsequent operation.

This allows dual material molding with a standard machine. Industries Served Heavy Truck Equipment Agriculture Equipment Commercial Construction Equipment Recreational Equipment Industrial Automotive Niche Vehicle Material Handling Large Custom Parts Consumer Goods.