One of the most common manufacturing processes is injection molding, where parts are produced by injecting liquid-form material into a mold. The process is used to create metals, glass and most commonly thermoplastic polymers. Injection molding heats small pellets of material to molten liquid, with that liquid then dispersed through a nozzle into a mold whose internal cavity fits the part being created. After cooling, the molten parts are removed from the mold using ejector pins.
Injection molding has a number of benefits, one of the most prominent being its ease of automation. This allows for very high rates of production, with mass production easily accomplished for highly detailed parts. Injection molding is also flexible in regard to different materials, as well as combinations of them, which is called co-injection molding. Additionally, the process is very efficient, since leftover material can simply be repurposed for re-use.
Some people are uncertain of the differences between injection-molding and 3D printing. Both can be beneficial to your business. Take a look at how you can incorporate them.
3D Printing: A Viable Alternative
A relative newcomer, 3D printing has seen advances over the years that have made it very much a viable alternative to injection molding. It's especially ideal for smaller-scale projects and ones whose dimensions aren't rigidly specified. Three-dimensional printing is a process where a 3D object is synthesized via a layer-based approach handled by inputted commands on a computer. Essentially, 3D printing creates a physical object from a digital blueprint. Thin layers are the basis of a 3D printer's creative process.
Three-dimensional printing, also known as additive manufacturing, addresses the issue of costly prototype parts that would take weeks to produce and deliver. With 3D printing, those parts can now be printed overnight and delivered the next morning. Companies in need of fast work, as opposed to the longer but more detailed process of injection molding, should consider 3D printing.
Potential Challenges Of 3D Printing
Growing technology in the additive manufacturing shield has resulted in more businesses using 3D printing than ever before, though there remain challenges that will hopefully be addressed by future developments. One of the most notable is quality.
Three-dimensional printing can be similar to other alternatives that are often cheaper and build quicker, in that material quality can occasionally be sacrificed for speed and output. While 3D printing has been found to produce molds up to 90 percent quicker and 70 percent cheaper than conventional mold-making, that may mean cutting some corners.
Three-dimensional printing is the fastest process in regard to creating molds, though 3D printing has several points of concern that may highlight injection molding advantages. Being aware of 3D printing’s comparative disadvantages can help businesses evaluate whether it’s worth investing in it, either as the sole process or a collaborative addition to injection molding. These include:
- Size limitations — With prints often limited to about the size of a grapefruit, without modern additives, injection molding is the better choice for larger-scale projects, especially with the capacity to produce parts about six times larger than 3D printing.
- Jagged edges — Since 3D printed materials are produced in layers, there’s always the possibility for angled surfaces or walls that require machining or sanding. This can take away from 3D printing’s quicker-time benefit.
- Less-durable material — 3D printing’s plastic molds feel hard, though they can break down fairly quickly if subjected to the demanding temperature process of injection molding, where steel and aluminum molds are exposed to 500-degree F temperatures or higher.
- Longer cycle times — These are common for injection molding, though 3D printing also requires polymer flow to be oriented in the exact same direction as 3D print lines to avoid sticking.
3D Printing And Injection Molding: A Productive Coexistence
Rather than tirelessly compare the pros and cons of 3D printing and injection molding, many manufacturers have found it more productive to use both methods in their facilities. Three-dimensional printing is a great tool for producing parts, while actual molds are still most durably created via injection molding. A time-sensitive mold assignment can also be accomplished by 3D printing, though, even with sacrifices on the quality end.
While some manufacturers have a rigid process, like exclusively producing a limited number of either small-scale or large-scale projects, that makes one method particularly more appealing, those with diverse assignments can use both. Large manufacturing volume may be needed for a specific output, where injection molding becomes favored, while another client may request a smaller-scale product with a nearby deliverable date, making 3D printing more ideal.
While the two are entirely different in their processes, the more accessible price point of 3D printing makes it a worthwhile consideration for any business with pre-established injection molding processes, which are more costly. Adding injection molding is more costly than adding 3D printing, but the investment is well worth it since material requests often vary in regard to size and delivery time.
All manufacturers that are frequently provided varying requests in regard to size and delivery time should consider both injection molding and 3D printing. With both processes at their disposal, manufacturers should be able to accommodate an eclectic range of requests from clientele, with considerable satisfaction.
Megan Ray Nichols is a freelance science writer.