How it works

Injection Molding is a manufacturing process for producing parts in large volume. It is most typically used in mass-production processes, where the same part is being created thousands or millions of times.     Plastic Injection Molding Materials : There are many varieties of materials that will be utilized in the injection molding process. Most polymers are all thermoplastics, some thermosets and a few elastomers. Each material needs a different set of processing parameters within the injection molding process. As well as the injection temperature, injection pressure, mold temperature, ejection temperature and cycle time. A comparison of commonly used materials : Injection Molding Materials Plastic Injection Molding Process : Plastic injection molding is out and away the foremost common thanks to manufacture large volumes of finished plastic elements for each reasonably commercial and industrial use. One cycle to make a finished part may take anywhere from a couple of seconds to minutes depending on part quality and size. We've got provided a detailed breakdown of the process : Injection Molding Process Plastic Injection Molding Tolerances : All plastic material will expand and contract under the influence of heat and moisture. Our tolerance guide will give more general information on the characteristics of most common resin types for typical part features. We will work closely with you to optimize your designs for manufacturing. We will indicate any areas where poor design may produce thermal stress, shrinkage, warping, etc....

Applications

Plastic injection molding is the preferred process for manufacturing plastic parts. Injection molding is used to create many things such as electronic housings, containers, bottle caps, automotive interiors, combs, and most other plastic products available today. It is ideal for producing high volumes of plastic parts due to the fact that several parts can be produced in each cycle by using multi-cavity injection molds. Some advantages of injection molding are high tolerance precision, repeatability, large material selection, low labor cost, minimal scrap losses, and little need to finish parts after molding. Some disadvantages of this process are expensive upfront tooling investment and process limitations.  

Traditional fabrication methods involve a great deal of effort, expense, and time. Specialists often have to create individualized molds, assemble multiple components, and construct items from multiple pieces. The process can involve many different materials, a wide variety of highly trained workers, and several expensive trials before the perfect object is finally created. Rapid Prototyping and 3D Printing remove some of the time and expense from the process of creating new commercial and industrial objects. Instead of utilitizing a factory to create a sample for testing, self-contained printers create items from three-dimensional CAD drawings. These items are printed one layer at a time, permitting more creativity and control over the final shape than any other construction method. Printing is also faster, cutting the creation process down from days or weeks to more hours for most items.

How does 3d-Printing Works?

The basic concept behind all 3D printers is the same. 3D CAD drawings are sliced into layers ranging from approximately 0.09 to 0.25 millimeters thick depending on the machine being used. Each slice represents a single layer of the constructed object. Different printers use different materials and different binding processes, but generally a powder of ceramic, nylon, or even metal is used as the base material and fused together into the pattern for the layer currently being created. After the completion of a layer, the machine moves on to the next layer until it is completed.

The State of 3D Printing Today

3D Printing and Rapid Prototyping have become more and more prominent in the past few years as new materials and processes have expanded the capabilities and lowered the cost to the point where small businesses and even individual consumers can now afford to create their own 3D objects. There’s even an open source 3D printer designed by Carnegie Mellon that can be built at home for only $2,400. 3D Printing is moving from a prototyping system to a manufacturing system in some industries. For example, the UK-based Atkins Project is investigating the use of 3D printers to manufacture lightweight, aerodynamic parts for aircraft that cannot be produced through more conventional methods. This manufacturing method also has the advantage of efficient use of materials; scraps of titanium and other expensive materials that would otherwise be unusable with traditional manufacturing methods can be reused with 3D Printing. Companies are offering specialized custom printing services aimed at niche users. For example, 3D Outlook Corporation offers 3-dimensional topographical maps aimed at hikers, real estate moguls, resorts, and others. Several new companies print models of avatars designed for various online games and virtual worlds. Although no longer available, there was even a service that let kids design and print their own superhero figures.

The Future of 3D Printing

3D printing is moving in several directions at this time and all indications are that it will continue to expand in many areas in the future. Some of the most promising areas include medical applications, custom parts replacement, and customized consumer products. As materials improve and costs go down, other applications we can barely imagine today will become possible. Perhaps the greatest area of potential growth for 3D printing is in the medical field. As mentioned above, researchers are just starting to experiment with the idea of creating artificial bones with 3D printers, but the process could potentially be used for so much more. Some companies are investigating the possibility of printing organic materials; these materials could be used in a much wider array of surgeries and potentially replace a much larger selection of defective human parts. Expect expansion of training techniques based on 3D printed models of complex human systems, a greater effort to more explicitly explain surgeries or the workings of the human body to patients as detailed replicas of body parts to become more common, and more precise surgical and diagnostic equipment based on designs that can be printed but not manufactured using traditional means. There is certainly a market for customized keepsakes and 3D printing can take that industry to new heights. There may come a time when choosing new cutlery doesn’t involve selecting a pattern at the store but designing it on your computer and printing out the resulting pieces. One day we may dial up just the right level of edge for a child starting to use sharp knives, build customized ergonomic handles that fit each individual’s hands perfectly (perhaps color coded for easy identification), or shape spoon bowls to generate the perfect mouthful every time. Another area of growth in the 3D printing arena is replacement parts production. Need a new screw for your laptop? A new gear for your heirloom grandfather clock? A new piston for your car? Instead of trying to track down the part, pay for shipping, and waiting weeks for its arrival, you’ll just be able to print it out and go. Mechanics will keep specs for every part of every car ever sold in a database and print out whatever they need immediately with no difficulty. While it would save time and money for any part, it’s a particular boon for restoration jobs of all kinds where the original parts are extremely difficult to find or may not even exist anymore.  

The uses of 3D printing are endless. From doctors and dentists to architects, from students to designers, from manufacturing to small business. From the start in the ’70s/’80s, when only big companies and industries could afford a 3D printer, things are changed a lot: nowadays the 3D printing market is bursting with new products that offer slightly different opportunities. The places itself among all of them with a very unique idea: reaching all the different areas of interest as it can turn itself into different machines.

Introduction

3D printing creates parts by building up objects one layer at a time. This method offers many advantages over traditional manufacturing techniques (for example CNC machining), the most important of which that apply to the industry as a whole are covered in this article. 3D printing is unlikely to replace many traditional manufacturing methods yet there are many applications where a 3D printer is able to deliver a design quickly, with high accuracy from a functional material. Understanding the advantages of 3D printing allows designers to make better decisions when selecting a manufacturing process and enables them to delivery an optimal product.

Speed

One of the main advantages of additive manufacture is the speed at which parts can be produced compared to traditional manufacturing methods. Complex designs can be uploaded from a CAD model and printed in a few hours. The advantage of this is the rapid verification and development of design ideas. Where in the past it may have taken days or even weeks to receive a prototype, additive manufacturing places a model in the hands of the designer within a few hours. While the more industrial additive manufacturing machines take longer to print and post-process a part, the ability to produce functional end parts at low to mid volumes offers a huge time-saving advantage when compared to traditional manufacturing techniques (often the lead time on an injection molding die alone can be weeks).

Cost

The cost of manufacture can be broken down into 3 categories: machine operation costs, material cost and labor costs. Machine operation costs: Most desktop 3D printers use the same amount of power as a laptop computer. Industrial additive manufacturing technologies consume a high amount of energy to produce a single part. However, the ability to produce complex geometries in a single step results in higher efficiency and turnaround. Machine operation costs are typically the lowest contributor to the overall cost of manufacture. Material costs: The material cost for additive manufacturing varies significantly by technology. Desktop FDM printers use filament coils that cost around $25 per kg, while SLA printing requires resin that retails around $150 per liter. The range of materials available for additive manufacturing makes quantifying a comparison with traditional manufacturing difficult. Nylon powder used in SLS costs around $70 per kg, while comparable nylon pellets used in injection molding can be purchased for as little as $2 - $5 per kg. Material costs are the biggest contributor to the cost of a part made via additive manufacturing. Labor costs: One of the main advantages of 3D printing is the the low cost of labor. Post-processing aside, the majority of 3D printers only require an operator to press a button. The machine then follows a completely automated process to produce the part. Compared to traditional manufacturing, where highly skilled machinists and operators are typically required, the labor costs for a 3D printer are almost zero. Additive manufacturing at low volumes is very competitively costed compared to traditional manufacturing. For the production of prototypes that verify form and fit, it is significantly cheaper than other alternative manufacturing methods (e.g. injection molding) and is often competitive for manufacturing one-off functional parts. Traditional manufacturing techniques become more cost-effective as volume increases and the high setup costs are justified by the large volumes of production.

Single Step Manufacturing

One of the biggest concerns for a designer is how to manufacture a part as efficiently as possible. Most parts require a large number of manufacturing steps to be produce by traditional technologies. The order these steps occur affects the quality and manufacturability of the design. Consider a custom steel bracket that is made via traditional manufacturing methods: Similarly to additive manufacturing, the process begins with a CAD model. Once the design is finalized, fabrication begins with first cutting the steel profiles to size. The profiles are then clamped into position and welded one at a time to form the bracket. Sometimes a custom jig will need to be made up to ensure all components are correctly aligned. The welds are then polished to give a good surface finish. Next holes are drilled so the bracket can be mounted on the wall. Finally, the bracket is sandblasted, primed and painted to improve its appearance. Additive manufacturing machines complete a build in one step, with no interaction from the machine operator during the build phase. As soon as the CAD design is finalized, it can be uploaded to the machine and printed in one step in a couple of hours. The ability to produce a part in one step greatly reduces the dependence on different manufacturing processes (machining, welding, painting) and gives the designer greater control over the final product.