The Clamping And Ejection System
On the far side of an injection molding machine is the clamping system. The clamping system has a dual purpose: it keeps the 2 parts of the mold tightly shut during injection and it pushes the part out of the mold after it opens.
After the part is ejected, it falls onto a conveyor belt or a bucket for storage and the cycle starts over again.
Alignment of the different moving parts of the mold is never perfect though. This causes the creation of 2 common imperfections that are visible on almost every injection molded part:
- Parting lines which are visible on the side of a part where the 2 halves of the mold meet. They are caused by tiny misalignments and the slightly rounded edges of the mold.
– Ejector marks which are visible on the hidden B-side of the part. They are created because the ejector pins are slightly protruding above or indented below the surface of the mold.
The image below shows the mold used to manufacture both sides of the casing for a remote controller. Quick quiz: try to locate the core , the cavity , the runner system, the ejector pins, the side-action core and the air vents on this mold.
Gate Locations And Material Flow
Along with ejector pin locations and part lines, it is also important to know where to have the gate locations. Gates are where the molten plastic enters the cavity of the part in the mold. These gates, once the part cools, leave a mark/ indication of where the gate was, even when attempted to be removed by a post process. Gate location is sometimes determined by:
- where it will be less noticeable
- where it will not interfere with the rest of the part
- how the plastic material will flow evenly through the part
- or a combination of all these.
Step : Removing The Runner And Packaging
Although the injection molding machines cycle ends on Step 5, the process continues. Periodically the machine operators, or robots separate the usable parts from the left over runner.* The runner is the pathway that the plastic takes to fill the mold cavity. 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.
Step 6 of the Injection Molding Process
*Note: Molds with hot runner systems may not have a runner or waste because the pathway is maintained at a constant heat.
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Injection Molding Defects Caused By Poor Mold Design Or Maintenance
Defects can be introduced into molded products by issues with the mold tooling itself. Certain defects are likely to occur when the mold is poorly maintained or designed. Especially in the latter case, these defects can be difficult or costly to address in future production runs when its necessary to completely overhaul the mold.
What Are Some Of The Considerations For Injection Molding:
Before you endeavor to produce a part via injection molding consider a few of the following things:
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What Die Cast Operators Do
In this section, we take a look at the annual salaries of other professions. Take Die Cast Operator for example. On average, the Die Cast Operators annual salary is $10,187 lower than what Injection Molding Technicians make on average every year.
While their salaries may differ, one common ground between Injection Molding Technicians and Die Cast Operators are a few of the skills required in each craft. In both careers, employees bring forth skills like Hand Tools, ISO, and Quality Checks.
As far as similarities go, this is where it ends because an Injection Molding Technician responsibility requires skills such as “Plastic Parts,” “Preventive Maintenance,” “Auxiliary Equipment,” and “Mold Changes.” Whereas a Die Cast Operator is skilled in “Trim Press,” “Cast Parts,” “Die Repair,” and “Aluminum.” So if you’re looking for what truly separates the two careers, you’ve found it.
Die Cast Operators tend to reach similar levels of education than Injection Molding Technicians. In fact, Die Cast Operators are 3.0% less likely to graduate with a Master’s Degree and 0.4% less likely to have a Doctoral Degree.
How To Lower Costs Of Injection Molding With Quick Mold Change Systems
One of the best practices requires a fully automated mold change. Not only will this decrease change over time, but it will also make the manufacturer a lot more flexible in his production quantity. An example of this is shown and explained in the article on the demonstration setup as made by Krauss Maffei, MundiMold and EAS change systems. Read more on how this co-creation led to a showstopper at the K2013.
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With Precise Tooling And High
Stratasys Direct has decades of experience in all phases of tooling, including part design, tool design, material sciences, post-processing and project management. Capabilities include injection molding, pad printing, silk screening, painting, EMI/RFI shielding and light assembly.
For streamlined operations, we offer Fast Track tooling, an operation that delivers parts in as little as ten days at volumes of 25 to 1,000 units.
Whatever the project, industrial designers, engineers and product designers may face some challenges when designing for injection molding. The following details three mistakes designers should avoid for successful injection molded parts.
What Do Injection Molding Machine Operators Do
After a setter has prepared the injection machine, an injection molder machine operator controls the machines that are used to mold materials like plastic and rubber. In this job, your responsibilities include adding the material into the machine, adjusting the speed of the machine, and monitoring the process to ensure the operations are meeting specifications. Your duties also include making periodic inspections of the equipment. Some issues are small enough that you can fix them yourself. For larger issues, you notify an industrial mechanic.
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Mount The Original Model Into The First Half Of The Mold Frame
I super-glued a round piece of plastic to the model . This was used to suspend the fish in the cavity of the mold frame. It also forms a channel that allows the melted plastic to enter into the mold during the final injection step.Note: this mold frame had cutouts for sprues on all 4 sides, so I had to block the other three cutouts. But, I noticed that the epoxy mold frames on the www.techkits.comwebsite now only have a single sprue cutout, so this may no longer be necessary.
How To Review/approve The Dfm Report
Review the Fictiv analysis on each DFM topic in the DFM report. You may receive one of the following analyses on each DFM topic.
The green box indicates that your part is acceptable on the DFM topic.
The orange box indicates that some changes are recommended on the DFM topic. Please upload part or drawing revisions to your Fictiv quote if needed.
The red box indicates that some changes are required on the DFM topic. Please upload part or drawing revisions to your Fictiv quote so that your part can be injection molded.
If you have any questions about our analysis, please add comments to the corresponding slide in the PowerPoint file. Use field under the Fictiv analysis box or insert text and shape directly into the slide.
After the Injection Molding tooling deposit is made, you will receive PEG reports . PEG stands for Parting line split, Ejection outline, and Gate location. These 3 aspects of tooling design require your approval before we begin manufacturing your parts. Please check the box I approve the analysis on this slide and enter the date of approval in the approval box in each slide of the PEG report to provide your approval.
After you review each slide and provide comments/approval, save the PowerPoint file and click Upload DFM report to upload it to our platform. Our quoting engineers will then either proceed with your quote or respond to your feedback by uploading a new DFM report.
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Manufacturing And Qc Blog
- Manufacturing and QC blog
- 11 Injection Molding Defects and How to Prevent Them
Theres a lot of room for expensive errors when it comes to injection molding. Quality issues in injection-molded products can range from minor surface defects to more serious problems that can affect the safety, performance and function of the product. They can be caused by problems related to the molding process, material use, tooling design or a combination of all three.
But as with any quality problems, knowing how molding defects arise is half the battle . As an importer or manufacturer of injection-molded products, some knowledge of common molding defects and how to avoid them can help you cut costs related to unsellable goods and product returns.
Lets look at the most common quality defects related to injection molding, what causes them and what you can do to prevent them.
Injection Molding: What It Is How It Works Who Is It For
Ronan Ye
Rapid Prototyping & Rapid Manufacturing Expert
Specialize in CNC machining, 3D printing, urethane casting, rapid tooling, injection molding, metal casting, sheet metal and extrusion
Injection molding is the most popular method for manufacturing plastic parts on the planet, so its not surprising that the global market for the process was valued at almost 260 million U.S. dollars, with projections for continued growth in the foreseeable future.
The technology is used in a wide variety of industries, including aerospace, medical equipment, and automotive, where advanced techniques such as overmolding and insert molding are used to create even the most complex parts with impeccable precision.
And when you consider just the wide range of injection molding benefits, understanding why millions of companies in some of the most demanding industries in the world are using it for bringing their part designs to life.
But why is injection molding machine manufacturing so effective? And how does it work?
To find out, lets dig into the subject and answer all of the important questions, including what it is, the process behind it, its main advantages, and how to choose the right service provider.
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What Are Injection Molding Jobs
Injecting molding is the process of filling molds of different shapes and sizes with heated materials, such as plastic or rubber, to make components or a finished product according to specifications for a wide variety of uses, from airplane and car parts to toys to medical devices. Some of the jobs available in injection molding include machine operator, fabricator, molding line assistant, technician, and molding line operator. Generally, these jobs are split between the workers who set up and calibrate injection molding machines and those who operate the machines. Most injection molding jobs are in factories or manufacturing facilities.
Molding Defects Often Caused By Process Problems
Some molding defects may be difficult or costly to address. Others can be prevented by adjusting the molding process, without the need to redesign the mold tooling or replace other production equipment. You can typically avoid these defects relatively easily simply by adjusting the flow rate, temperature or pressure of your mold.
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Case Study: Using A Plastic Injection Mold To Create A Gutter Cleaning Tool
Recently, we had an entrepreneurial client come to us with an idea for a plastic part. He had jury-rigged an innovative gutter cleaner from parts he bought at a local hardware store. On his own, he produced about a dozen gutter cleaners. But he needed to scale his production to make the product commercially viable. He came to our team at Rex Plastics to find out whether plastic injection molding was right for his design.
After reviewing the hand-made prototype, we recommended that he use injection molding for the following reasons:
- The plastic part was smaller than 40g.
- The client needed to manufacture more than 1000 plastic parts per year.
- The plastic parts wall thickness was uniform.
- The plastic part could be made from a thermoplastic material.
- The function of the plastic part was more important than its aesthetics.
- The client could wait several months before starting mass production.
We were able to design a mold for the gutter cleaner, build a prototype, tool the mold, and begin production in just a few months.
Today, the client purchases thousands per year, and order quantities for his gutter cleaner are climbing steadily.
Description Of A Die Caster
The fourth career we look at typically earns lower pay than Injection Molding Technicians. On average, Die Casters earn a difference of $18,103 lower per year.
While their salaries may vary, Injection Molding Technicians and Die Casters both use similar skills to perform their jobs. Resumes from both professions include skills like “Hand Tools,” “Quality Standards,” and “Trouble Shooting. “
While some skills are shared by these professions, there are some differences to note. “Plastic Parts,” “Preventive Maintenance,” “Auxiliary Equipment,” and “Mold Changes” are skills that have shown up on Injection Molding Technicians resumes. Additionally, Die Caster uses skills like Die Repair, Cast Machine, Cast Parts, and Inspect Parts on their resumes.
In general, Die Casters reach similar levels of education when compared to Injection Molding Technicians resumes. Die Casters are 4.6% less likely to earn their Master’s Degree and 0.4% less likely to graduate with a Doctoral Degree.
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Thoughts On Diy Injection Mold Design For The Home Shop
Uhh. There are plenty of reasons why a fairly complex mold couldnt be produced by the home gamer. They would have to already have high end CNC equipment and knowledge of how to use it just to start with, even if you set aside the mold design software part of thing and started with finished CAD drawings.
Setting aside the fact that you have to design a proper mold as well as deal with all of the other nuances of injection molding plastic, hand-waving this and just saying it can be done with a 3D printer is not just inaccurate but unprofessional.
That all said, I would really like it if injection molding were to become easier to do and much less expensive. But unlike a mill, CNC molding doesnt really scale down in the same way because the pressures involved dont suddenly change when you scale things down, necessitating proper, high quality equipment that doesnt really drop much in price unless you were to cut out basically everything and make it a few thousand dollars of nearly all manual work. At least the controls and such are getting easier to deal with and less expensive.
Your typical home 3D printer certainly leaves a lot to be desired in terms of finish but get your designs printed on a commercial sls machine and the results are rather spectacular. I know of a few parts now been made this way in low volumes for the VW bus restoration scene.
Start Small And Prototype Fast
Before you commit to any expensive injection molding tooling, first create and test a functional prototype of your design.
This step is essential for launching a successful product. This way design errors can be identified early, while the cost of change is still low.
There are 3 solutions for prototyping:
Use the information below as a quick comparison guide to decide which solution is best for your application.
Prototyping with 3D printing
Prototyping with low-run injection molding
Min. quantity: 10 – 100 partsTypical cost: $1000 – $4000 totalLead time: 5 – 10 days
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Introduction To Injection Molding For Mass Production Of Custom Plastic Parts
Although 3D printing is the technology used for prototyping custom plastic parts, injection molding is the technology used for mass manufacturing.
Unless your electronic product will be marketed solely to DIYers and electronics hobbyists its going to need an enclosure. Most likely this enclosure will be made of plastic.
Injection molding is going be a big part of your journey to market. Regardless of your technical background you at least need to understand injection molding at a basic level.
Many entrepreneurs are surprised to learn that while the electronics will likely be the most expensive to develop, the plastic enclosure will be the most expensive to scale to manufacturing.
This is primarily due to the high cost of the injection molds. In fact, mold cost is one of the biggest expenses when taking a product from concept to market.
