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Thin wall injection molding is a specialized form of conventional injection molding that focuses on mass-producing plastic parts that are thin and light so that material cost savings can be made and cycle times can be as short as possible.

Shorter cycle times means higher productivity and lower costs per part. The definition of thin wall is really about the size of the part compared to its wall thickness. For any particular plastic part, as the wall thickness reduces the harder it is to manufacture using the injection molding process. The size of a part puts a limit on how thin the wall thickness can be. For packaging containers thin wall means wall thicknesses that are less than 0. The trend towards thin wall molding continues to increase in many plastic industries as plastic material and energy costs continue to rise and delivery lead times are squeezed.

Plastic resins suitable for thin-wall molding should have high-flow properties, particularly low melt viscosity. In addition, they need to be robust enough to avoid degradation from the heat generated by high shear rates high injection speeds [5].

Some plastic manufacturers make plastics specifically for thin wall applications that have excellent flow properties inside the mold cavity. For example, plastic manufacturer Sabic has a polypropylene food contact grade plastic which is specifically designed for thin wall margarine containers and lids. Another plastic manufacturer, Bayermakes a blend of Polycarbonate PC and Acrylonitrile butadiene styrene ABS specifically designed to make thin wall mobile housings.

Compared to conventional injection molding, thin wall molding requires molding machines that are designed and built to withstand higher stresses and injection pressures. The molding machines computer control should also be precise in order to make quality parts.

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For this reason these molding machines are more expensive than general purpose machines. Thin-wall-capable machines usually also have accumulator-assisted clamps to accommodate fast cycle times.

Regular maintenance schedules must be completed so that the machine and part quality does not suffer. As with the injection molding machines, injection molds need to be robust enough to withstand high stresses and pressures.

The mold must also have a well designed cooling system so that heat can be quickly extracted from the hot plastic part allowing fast cycle times. To achieve this, cooling channels need to be designed close to the molding surface. Cleaning the mould on a daily basis is also a critical requirement to maintain the part quality. In countries where manual labour is expensive, robots are commonly used to remove the plastic parts from the mold and order them into equal stacks.

These robots are fixed to the molding machine and need to be fast and reliable. The range of process parameters, which are employed for thin wall molded parts, is considerably narrower than that of conventional injection molding because thin parts are difficult for the injection unit of the machine to fill compared to thicker parts.

Even with optimally designed parts and molds, it is still more difficult to produce parts with thin walls. Consistent injection speeds and pressures are required to maintain the quality of the parts produced from thin wall molding. A properly trained molding technician who understands and operates the machine within the confines of the narrow processing window at which the molded product's production cost-effectiveness is optimized will ensure that the process produces quality parts during the production.

From Wikipedia, the free encyclopedia. Categories : Injection molding Industrial design. Namespaces Article Talk. Views Read Edit View history. By using this site, you agree to the Terms of Use and Privacy Policy.For most of our biggest investments — both in our personal and professional lives — regular maintenance is often at the forefront of our minds. It makes sense, then, that injection mold maintenance should be a major concern. These molds can often cost tens or hundreds of thousands of dollars to fabricate — often more than your automobile, maybe even more than your house.

Injection molding machine maintenance is a just-as-important — though less-overlooked — component of the process. Injection molds undergo a lot of stress in the course of carrying out the molding process. Depending on the design of your mold, factors like temperature fluctuations, opening and closing of the mold, ejector pin action, and other movements can all cause natural wear and tear on a mold.

A good injection mold will be designed to handle this wear and tear, but unpredictable situations can still arise as a result of these numerous stresses and the nearly innumerable permutations in which they can interact.

Temperature fluctuations, for instance, can cause both internal and external stress on the mold. Especially if the mold is not designed in such a way as to allow for more uniform cooling, molds can expand and contract in response to heating and cooling, and can weaken from the stress — and potentially even crack.

Ejector pins may not function properly after a certain number of molding cycles. Aside from the aspects inherent to the mold itself, there are also maintenance issues related to the material injected into the mold.

As the mold completes more and more cycles, minute amounts of material residue can begin to collect inside the mold cavities. Over time, these deposits can accumulate and affect the interior shape of the cavity — and thus, the shape of the finished part.

Deposits in mold runners or the mold cavity can also affect cycle time and, left unchecked, can even begin to prevent the substrate from reaching areas of the mold. If a mold is used with different materials, these deposits might also create unintended interactions, depending on the chemical makeup of those materials. This, in turn, can affect the structural integrity of the finished product, and creates risks for products used in food or medical applications.

The cost of repair or replacement might even be prohibitive, depending on the size of your business.

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In short, the repercussions of a major maintenance problem can potentially irreparably damage your bottom line — and your business. When done correctly, the time investment will not be prohibitive, either though the process should always be thorough. The answer to that question could probably be summed up in one word — awareness. Good mold design, following standard best practices to facilitate uniform cooling and minimized stress both internally and externally, is a great first step.

The ideal mold manufacturer will be able to help you work out elements like design and material selection while taking your budget into account. A knowledgeable manufacturer can also explain the benefits and limitations of your particular mold configuration, giving you a heads-up on what to look out for when you start your regular maintenance. From there, your maintenance will involve regular inspection, addressing the issues we talked about above.

Check runners and mold cavities for material deposits, and clean or otherwise remove them regularly, before they start creating defective parts. Monitor temperatures throughout a mold as it heats up and cools, and take necessary steps to attenuate irregular cooling.

Injection Mold Maintenance (excerpt)

You should also create a schedule or a plan for your injection mold maintenance, whether based on the calendar or the number of cycles run. Also, be sure to keep track of the data and information you collect in a centralized log, for easy reference. Share on facebook.

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Share on linkedin.Tool longevity is just as important to part cost and quality as the design and build. Regular, careful maintenance can prevent part failures and lower the overall cost of your injection molding program. Mold maintenance, or tool maintenance, refers to the cleaning and repairs that are needed to keep an injection mold in the best working order.

Maintenance is performed routinely over the life of the mold preventative maintenance or PMand also when any problems arise. The condition of the injection mold affects the quality of the plastic components produced.

Performing necessary preventative maintenance improves tool longevity and part quality by stopping issues before they happen. Over time, the molding process can cause wear on a mold. If you never perform regular maintenance, like changing the oil, the mechanical parts will experience wear, reduce running efficiency, and eventually fail.

Unfortunately, many molders will avoid doing maintenance until these quality problems arise or the tool breaks down. Repairing the mold at this point can be expensive and can jeopardize your part supply. However, if done regularly and correctly, preventative maintenance can improve production and lower the overall cost of owning the tool.

A well maintained and designed mold is key to producing consistent, high quality injection molded parts. Ensuring a quality mold requires well-designed tooling and higher precision build, both of which can increase the tool construction cost and regular maintenance cost.

However, these measures will ultimately save you significant costs on repairs. As a best practice, choose a molder that performs maintenance, such as cleaning parting lines during the production run, and has a dedicated service team that documents and tracks mold maintenance, to ensure that your tooling gets the long-term care it needs.

Working with your supplier as a strategic partner can help reduce many of the risks and costs associated with injection molding. They can help you:. The complexity of the part design drives the tool design. Working with your supplier to optimize both part design and mold design can improve the longevity of the tool and the quality of the part.

Often simple feature changes can improve the robustness of the tool, simplify manufacturing, and ensure consistent part quality. Over-investing wastes money, but under-investing results in a shorter mold lifespan, supplier reliability issues, and added costs. Added expenses can include reactive tool maintenance while the tool should be producing parts, as well as overall mold maintenance and repair over the life of the tool.

Empire designs molds to make the PM process easier on the customer.

injection molding maintenance

We establish a unique PM cycle for every mold depending on the specific part design, industry, material, and other factors. By providing multi-level maintenance—ranging from a basic cleaning and wear assessment to a higher level teardown with a complete inspection—on a scheduled rotation that is fully documented at each service interval, we can ensure that your mold functions properly each time it is put to use.

There are many options for making prototype parts. For specific applications such as high-cavitation precision parts with complex tools, a production intent prototype mold that replicates cooling, gating, and ejection strategies will lower the risks associated with production molds. Empire also builds components so that they can be removed individually without having to disassemble the whole tool, which saves maintenance time and improves tool longevity.

Having issues with your tool? It has been republished with new and updated information.

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What is mold maintenance? Why is mold maintenance important? What problems does mold neglect cause?


Download our guide, Diagnosing Plastic Part Failure, to learn how we assess part defects and molding issues. What are the benefits of a properly maintained mold? How can your supplier help? They can help you: Optimize part design and mold design The complexity of the part design drives the tool design.The disassembly and maintenance of the double alloy screw nozzle of the injection molding machine is a problem that many users have been very concerned about.


Here we will teach you how to replace and install the screw correctly and effectively. After reading this article, many of your puzzled questions will be solved! The disassembly of the injection nozzle of the injection molding machine is done after the cleaning of the inner wall of the barrel and the nozzle.

injection molding maintenance

First remove the protective cover outside the barrel, the heater outside the nozzle and the hot spot coupling, remove the surface materials and dust and other dirt; hit it with a special hammer to loosen it, and then loosen the connecting bolt with a wrench. At this time, it is not advisable to loosen them completely to prevent the gas in the barrel from spraying and hurting people; after the internal gas is released, the bolts are loosened with snow and then the nozzle is removed.

Disassembly of the double alloy screw nozzle of the injection molding machine If there is residual material in the barrel, it should be heated to the plasticizing temperature first, using polyolefin resin with high thermal stability or special cleaning material for the barrel, and fully perform high-speed cleaning, and try to discharge the remaining molten material before entering the disassembly. Work, because the residual material at the nozzle part is always impossible to be discharged, so the nozzle or barrel head should be heated, and then the nozzle is disassembled.

After the injection nozzle of the double-alloy screw of the injection molding machine heats up, tap it with a special hammer to loosen it. It is not appropriate to loosen all the bolts. After the internal gas is released, remove the nozzle. The cleaning of the dual alloy screw nozzle of the injection molding machine should be carried out at high temperature while it is hot, so as to remove the residual melt in the flow channel from the nozzle hole.

The method is to inject the mold release agent from the nozzle to the inside, that is, to infiltrate the mold release agent from the side of the nozzle thread to the material and the inner wall wall surface, so that the material is separated from the inner wall, thereby removing the material from the nozzle.

Second, the maintenance of injection molding machine double alloy screw nozzle If there is one-sided contact or poor contact between the nozzle and the mold positioning sleeve during production, the spherical R part of the front end will be deformed, forming a groove for the melt to escape, resulting in flash at the nozzle, and the caliber part will also appear Deformation, so the overflow should be checked and repaired in time. The thread of the nozzle should be checked regularly Focus on checking the integrity of the part and the sealing surface on the side of the barrel.

If serious wear or corrosion is found, it should be replaced in time. Check the internal channel of the double alloy screw nozzle of the injection molding machine By air injection can observe the surface quality of the molten material strip, and the residual molten material discharged from the nozzle can more accurately reproduce the flow channel condition in the nozzle. This can analyze the residual amount of melt in the nozzle and the temperature distribution.

News Company News Industry News. Disassembly and maintenance of double alloy screw nozzle of injection molding machine.

Summary: The disassembly and maintenance of the double alloy scr […]. Zhoushan Batten Machinery Technology Co. Address : No. E-mail: sales batten-machinery.

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Web: www.Mould, indispensable in modern industry development and technological level improvement, is one kind of widely-used process equipment during mid-period of industrial production. Mould can be classified as cold-punching mold, injection mold or plastic injection molddie casting mold, rubber mold and so on. By gate type: edge gate mould, pin gate mould, hot runner mold. It is classified as the main runner, sub-runner, runner gate, cold slag well, etc. Demoulding structure : It is the structure ejecting the plastic part from the mold.

Temperature conditioning system : Cooling water must installed at both cavity and core site to meet the requirement of mold temperature during the injection molding process. Side parting line and side action : Slide should be adopted when there is under-cut structure on the product design, i.

It is usually made up by slide, lifter, loose core, etc. Venting system : It consists of two forms: the venting groove and gap between mould components.

In order to discharge air in cavity and gas caused in moulding process, venting groove is usually set at parting line, with the principle of designing venting groove as big as possible in compliance with smooth overflow and flashing. Meanwhile, insert pin, ejector pin and mould insert discharge air through gaps between mold components.

Mould repair is needed during occasions of normal or abnormal abrasion and various abnormal phenomena occurred during plastic molding production. Precise understanding for repair work needed to be done : Mould repair is usually carried out without drawing with the principle of no change of the plastic parts structure and dimension.

Therefore, it is prerequisite for our technician to understand precisely where and to what size should the part be repaired. Sign mark : The corresponding sign mark in mould base must be remembered clearly when removing guide pin, ejector sleeve, ejector pin, mould insert, holder block, etc, to assure the right re-installation for the mould, especially for those with direction requirements. The following two items should be paid attention to in this process:. Anti-Damage proofing : Anti-Damage proofing should be carried out for parts easy to install.

In other words, parts cannot be installed back with Incorrect installation. Placement : Parts removed should be placed in order while screws, springs, O-ring should be stored in the plastic box. Protection : Protection measures should be made for precision parts such as mould core, cavity and so on, to avoid careless damage by people.

Plastic Injection Mold Maintenance

Polishing : Protection measures for texture surface component should be made prior to repair work when polishing is needed for plastic parts with mould sticking and scrapes. It is forbidden to polish texture surface area.

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Mould shutoff repair should be done if it is unsure for the repair result. Welding : The following items should be paid attention to during welding on texture surface:. Re-texture : When mould repair is finished and ready to take it out for re-texture, moldmaker should make good protection of texture area covered with paper, mark position to make texture area and attach texture template with the mould. After mould texturing, moldmaker should examine textured surface carefully to guarantee good quality and then install mould back.Welcome to a new column dedicated to improving efficiency in your tool room and the health and performance of your molds.

You can make this slide hammer and punch for tooling removal or you can buy it—complete with several sizes of punch blanks—from AWAM Machine Co. Tel: ; fax: Mikell Knights. This column will cover real-world maintenance issues from both the blue-collar and white-collar sides of the bench. This column will be directed toward injection molding shops—my own area of experience—but many of the principles discussed should be relevant to other types of plastics processing. For the vast majority of skilled trades—electricians, machinists, woodworkers, etc.

injection molding maintenance

There is a test to pass, blueprints to read, or a machine to master. So they assume they need to hire top-shelf tool makers, even though most toolmakers despise mold repair because it does not require their fabrication skills as much as solid mold troubleshooting experience. If he does, and if you ask him what he did, he will probably just give you a knowing wink and a tap on his temple.

Bob himself might not be quite sure why the problem went away. I have talked with many talented employees who want to improve mold-shop efficiency but are administratively handicapped. They get bogged down and burned out as their poorly equipped repair shops fill up with half-assembled molds waiting to be hand-cleaned or to be fitted with components that should have been in stock.

Supervisors bring in molds that have been victimized by water or oil leaks, missing parts, loose bolts, or being just plain pounded to death. Of course, no back-up molds are available, so the finger-pointing begins. Typical mold-maintenance functions such as disassembly, troubleshooting, repair, cleaning, and assembly can and should be standardized and formalized.

A systemized approach can bring significant benefits:.

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It must be a job requirement. Maintenance technicians must be accountable for what they do. This can occur only by shifting to a systemized approach to understanding and correcting mold defects. Through upcoming articles, I hope to show how this is accomplished. Steven Johnson worked as a toolmaker for 26 years, rebuilding and repairing multicavity molds for Calmar Inc.

He also founded MoldTrax in Ashland, Ohio, which designs and sells software for managing mold maintenance www. He can be reached at sales moldtrax. Removing close-tolerance tooling for cleaning, inspection, or replacement is one of many mold-repair jobs performed on a daily basis. Two important factors to consider when removing tooling are timing and technique. Tooling should be removed only after troubleshooting a part defect.

If you remove all the tooling before troubleshooting, then you have to sort through all the cores and cavities to find the one in question.Every complex machine requires maintenance.

You service your car to get better gas mileage and extend its life; we maintain our injection molds to keep them running smoothly and efficiently. The number of cycles run on an injection mold is a lot like the mileage on a car - certain operations must be done at prescribed intervals.

We can't do maintenance on all our molds at once, either, because they run at very different levels. Some are only required to run a few weeks per year, going through only a few thousand cycles.

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Others will run seven days a week all year long, accumulating millions of cycles. Basic preventative maintenance is done daily. We clean the mold parting line, applying proper lubrication to moving components. We also check for damage and wear that would affect safe mold operation and part quality.

This simple maintenance can be done while the mold is in the press. Depending on the complexity of the mold, larger-scale general maintenance is usually done according to cycle count, or how many times the mold has been run. Basic open-and-shut molds without complex action receive general maintenance between every M and M cycles. A mold with many moving parts requires a closer look, so we do general maintenance every M cycles. We inspect the last shot of parts from the mold for damage or defects.

If all is well there, we go ahead and disassemble the mold completely. The mold plates are cleaned and inspected for signs of wear, vent depths are checked, and O-rings are replaced. Any part of the mold that is defective or damaged is swapped out. If the mold we're cleaning is equipped with a hot runner, we check it for signs of leakage and inspect the condition of the components.

Then we reassemble the mold, run a thorough systems check, and ready it for production or storage. Between M and 1MM cycles, every mold undergoes major preventative maintenance. This process includes all of the steps done in general maintenance and takes a much more in-depth look. We measure the mold's alignment features, compare them to their baseline "new" condition, and replace them as necessary.

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