A 360-degree look at resin conveying systems: types, operation, economics, design, installation, components and controls.
This Knowledge Center provides an overview of resin moisture and the drying process, including information on the best drying practices for your manufacturing facility. Insert Mold
Everything you need to know about plastics compounding technology—from feeding solutions to application profiles and expert advice.
Combat the skilled labor shortage using this comprehensive resource to train your own plastics processing experts.
Deep dive into the basics of blending versus dosing, controls, maintenance, process integration and more.
This Knowledge Center provides an overview of the considerations needed to understand the purchase, operation, and maintenance of a process cooling system.
Learn about sustainable scrap reprocessing—this resource offers a deep dive into everything from granulator types and options, to service tips, videos and technical articles.
While price initiatives for PE and PVC were underway, resin prices had rollover potential for first two months of 2024, perhaps with the exception of PET.
Flat-to-downward trajectory for at least this month.
A mixed bag, though prices likely to be down if not flat for all this month.
Trajectory is generally flat-to-down for all commodity resins.
Flat-to-down trajectory underway for fourth quarter for commodity resins.
Generally, a bottoming-out appears to be the projected pricing trajectory.
Resin drying is a crucial, but often-misunderstood area. This collection includes details on why and what you need to dry, how to specify a dryer, and best practices.
Take a deep dive into all of the various aspects of part quoting to ensure you’ve got all the bases—as in costs—covered before preparing your customer’s quote for services.
In this collection of articles, two of the industry’s foremost authorities on screw design — Jim Frankand and Mark Spalding — offer their sage advice on screw design...what works, what doesn’t, and what to look for when things start going wrong.
In this collection, which is part one of a series representing some of John’s finest work, we present you with five articles that we think you will refer to time and again as you look to solve problems, cut cycle times and improve the quality of the parts you mold.
Gifted with extraordinary technical know how and an authoritative yet plain English writing style, in this collection of articles Fattori offers his insights on a variety of molding-related topics that are bound to make your days on the production floor go a little bit better.
In this three-part collection, veteran molder and moldmaker Jim Fattori brings to bear his 40+ years of on-the-job experience and provides molders his “from the trenches” perspective on on the why, where and how of venting injection molds. Take the trial-and-error out of the molding venting process.
Mike Sepe has authored more than 25 ANTEC papers and more than 250 articles illustrating the importance of this interdisciplanary approach. In this collection, we present some of his best work during the years he has been contributing for Plastics Technology Magazine.
In this collection of content, we provide expert advice on welding from some of the leading authorities in the field, with tips on such matters as controls, as well as insights on how to solve common problems in welding.
Mold maintenance is critical, and with this collection of content we’ve bundled some of the very best advice we’ve published on repairing, maintaining, evaluating and even hanging molds on injection molding machines.
Thousands of people visit our Supplier Guide every day to source equipment and materials. Get in front of them with a free company profile.
A unique amorphous PHA has been shown to enhance the mechanical performance and accelerate the biodegradation of other compostable polymers PLA in blown film.
Oak Ridge National Laboratory's Sustainable Manufacturing Technologies Group helps industrial partners tackle the sustainability challenges presented by fiber-reinforced composite materials.
The first task in moisture measurement is to purchase an instrument that is based on sound fundamentals. Then, before it goes into use, method development must be undertaken for all polymers that are going to be processed in the plant.
From pre-show coverage to post-show coverage — with at the show coverage in between — you can rely on Plastics Technology to keep you informed on all things related to NPE2024.
Like December 2022, the December 2023 index represents increased activity following dips in November.
A development and manufacturing service provider is using dissolvable molds to build injection molded silicone prototypes.
If a printed tool only has a finite number of shots in it, why waste any of them on process development?
Follow these best practices to minimize loss of time, material and labor during color changes in molding containers from bottles to jerrycans. The authors explore what this means for each step of the process, from raw-material infeed to handling and reprocessing tails and trim.
I’m looking for a few good molders to help trial a new screw design, and share data and results for a future article to prove the benefits of a melt uniformity screw.
While price initiatives for PE and PVC were underway, resin prices had rollover potential for first two months of 2024, perhaps with the exception of PET.
Topping five other entries in voting by fellow molders, the Ultradent team talks about their Hot Shots sweep.
Serendipitous Learning Opportunities at PTXPO Underscore the Value of Being Present.
Introduced by Zeiger and Spark Industries at the PTXPO, the nozzle is designed for maximum heat transfer and uniformity with a continuous taper for self cleaning.
Ultradent's entry of its Umbrella cheek retractor took home the awards for Technical Sophistication and Achievement in Economics and Efficiency at PTXPO.
technotrans says climate protection, energy efficiency and customization will be key discussion topics at PTXPO as it displays its protemp flow 6 ultrasonic eco and the teco cs 90t 9.1 TCUs.
Shibaura discusses the upcoming Plastics Technology Expo (PTXPO) March 28-30
Competition will invite participants to help reshape life cycle management in plastics.
Sign up to attend North America’s leading trade show for plastics.
Offerings range from recycled, biobased, biodegradable and monomaterial structures that enhance recyclability to additives that are more efficient, sustainable and safer to use.
Ahead of the first NPE since 2018, PLASTICS announced that its triennial show will stay in Orlando and early May for ’27, ’30 and ’33.
New features of NPE2024 aim to “bring the whole plastics ecosystem together to innovate, collaborate and share findings.”
Hundreds of tons of demonstration products will be created at NPE2024 next spring. Commercial Plastics Recycling strives to recycle all of it.
Mixed in among thought leaders from leading suppliers to injection molders and mold makers at the 2023 Molding and MoldMaking conferences will be molders and toolmakers themselves.
After successfully introducing a combined conference for moldmakers and injection molders in 2022, Plastics Technology and MoldMaking Technology are once again joining forces for a tooling/molding two-for-one.
Multiple speakers at Molding 2023 will address the ways simulation can impact material substitution decisions, process profitability and simplification of mold design.
When, how, what and why to automate — leading robotics suppliers and forward-thinking moldmakers will share their insights on automating manufacturing at collocated event.
As self-imposed and government-issued sustainability mandates approach, injection molders reimagine their operations.
August 29-30 in Minneapolis all things injection molding and moldmaking will be happening at the Hyatt Regency — check out who’s speaking on what topics today.
Get your clicking finger in shape and sign up for all that we have in store for you in 2023.
Molding 2023 to take place Aug. 29-30 in Minnesota; Extrusion 2023 slated for Oct. 10-12 in Indiana.
Key technologies — such as multicolor molding, film molding and PUR overmolding for both exterior and interior applications — are at the forefront of this transformation. Join this webinar to explore the vast potential of eMobility in molding large components — including those with fiber reinforcements — thereby driving the need for large injection molding cells with a clamping force of up to 11,000 tons. You will also gain insight into Engel's innovative two-stage process, a solution for future recycling processes. This webinar will provide an in-depth overview of challenging applications, production concepts and best practices, including: BMW iX front panel production cell Smart rear panels concept based on IMD and 2C molding Sustainability concepts based on two-stage process Large tonnage equipment for battery moldings
In today's manufacturing environment, robust processes that meet strict industry and regulatory standards are essential. With the advent of servo-driven ultrasonic welding technology, enhancing product quality and maintaining consistency has become remarkably effortless. Discover the fundamentals of ultrasonic welding, delve into vital components within these systems, explore how servo-driven ultrasonic welding enhances weld quality via advanced control features and gain insights into optimizing your assemblies for welding in these high-performing machines. Join Dukane to unlock the potential of ultrasonic welding in modern manufacturing for plastic devices and components. Agenda: Fundamentals of ultrasonic welding Key components in an ultrasonic welding system Using servo-driven ultrasonic systems to control your welding process Designing your parts and components for servo-controlled ultrasonic welding
This webinar will help you make informed decisions to confirm the equipment access stairs in your facility are OSHA compliant and meet the highest standards of safety and ergonomics. Agenda: Identifying opportunities to increase safety in the work place Utilizing space saving stairways Ensuring code compliance for equipment access
4.0, EUROMAP, OPC, OLE, QC, DSN, SQL, VNC, MES, ERP, FTP, CMS, SPI — are you confused by all buzzwords being tossed around in the plastics industry? Not convinced the data collection is necessary? Or are you unsure of how it could be implemented and improve your molding processes? Wittmann has been on the cutting edge of the data collection push for nearly 20 years. In this webinar, take a step back from the idea of the manufacturing facility of the future and discuss what you can do today to improve your process. Using readily-available technology, Wittmann can help reduce downtime, limit scrap and wasted material, and predict required maintenance. Let the experts at Wittmann help you understand: what data can be collected, what that data can be used for, what systems are used, and how to implement them. Agenda: Demystifying the terminology Tracking the material flow and lot information through the material handling system The data available from various auxiliary equipment, such as: dryers, blenders, mold temperature controls and robots Automating the process through changes in the data collected at the machines during production Adding visualization to increase productivity
Learn how targeted, modular, dosing and blending solutions — covering powders, granules, regrinds and liquids — provide plastics processors of all kinds with best-in-class accurate dosing while delivering significant raw material savings and ensuring highest quality. Agenda: Introduction to Movacolor Blending in plastics applications Movacolor feeding and dosing technology Hybrid blending to combine high material throughput and dosing accuracy
This presentation will explore the in-situ polyurethane (PU) overmolding of injection-molded and composite parts, allowing for direct out-of-mold class "A" surfaces. KraussMaffei will review the process and equipment required. It will also discuss tooling types currently available for PU systems for this process. KraussMaffei will compare the pros and cons of this technology over currently-available coating and painting systems. Agenda: Introduction and evolution of the ColorForm technology Overview of the ColorForm process Equipment required Tooling and PU systems Benefits of the system compared to typical spray-applied coatings Pros and cons of the technology
The global plastics industry has been navigating through what is arguably the most volatile period in decades. Unprecedented amounts of new production capacity are scheduled to start in North America, Europe, and China in the near term and compete for demand during a period of economic challenges. How will trade flows shift? Will this lead to regional cost disparities and rationalization? Energy transition and sustainability targets continue transforming the plastics market and increasing the competitive landscape. As the market evolves, what impact will new technology, policy, regulation, the growing role of chemicals versus fuel and other factors have on industry restructuring and business models? At GPS 2024, leading global experts will come together to discuss pivotal impacts and initiatives shaping the plastics industry. Join us and participants from across the globe to gain the latest insight and deep analysis as you connect with your peers and industry professionals. This year’s conference will explore the theme Disruptive Global Dynamics Reshaping Plastics and include a full day workshop focused on the Global Plastics Business and Plastics Transition to Circularity, 1.5 days of expert content and numerous networking functions.
Every three years, leaders from almost every major industry gather at NPE to advance their businesses through innovations in plastics. The largest plastics trade show in the Americas, NPE offers six technology zones, keynote speakers, workshops and opportunities to build partnerships.
The 3D Printing Workshop @ NPE2024 – The Plastics Show, is an immersive, half-day workshop focused on the emerging possibilities for part production via 3D printing and additive manufacturing. Presented by Additive Manufacturing Media, Plastics Technology and MoldMaking Technology, the 3D Printing Workshop will build upon a successful model first introduced at IMTS 2014. Attendees will benefit from a program focused on practical applications of 3D technologies related to plastics processing. This event will conclude with a 3D Printing Industry Reception sponsored by Additive Manufacturing Media.
The Society Plastics Engineers (SPE) Extrusion Division and the SPE Eastern New England Section will co-host the Screw Design Conference-Topcon on June 19-20, 2024 @ UMass Lowell in Lowell, MA. This highly technical program will focus upon screw design principles for single and twin screw extruders with wide ranging topics relating to screw designs for feeding, melting, mixing, venting and pumping plastics products and parts. Areas of focus will include screw designs for melt temperature and gel management, gel minimization, bioplastics, recycled materials and foaming. In addition to the technical sessions, a tour of the UMass Lowel Plastics Processing Laboratories will be integrated into Day 2 of the event. This program is not just for screw designers, but to help anyone responsible for any type of extrusion operation to evaluate existing extrusion equipment; and also to prepare for future projects. Price to attend: Less than $1000! Registrations will be accepted in early 2024. Call for papers – To be considered to give a presentation, please submit a talk title and abstract on or before December 15 to: Technical Chair: Eldridge M. Mount III, e-mail emmount@msn.com Corporate sponsorships - A limited # of corporate sponsorships (15) are available on a 1st come basis. Included is a 6’ tabletop display (must fit on table), denotation in all promotional activities, and 1 no charge registration. To become a sponsor contact: Charlie Martin, Leistritz Extrusion, e-mail cmartin@leistritz-extrusion.com, cell 973-650 3137 General information: A reception on Day 1 and a tabletop display area will allow the attendees to meet and discuss state-of-the-art screw technologies with industry experts. The SPE Extrusion Division will issue a “Screw Design Certificate” to all participants who have attended the program. Students are encouraged to attend and will receive a discounted rate. For additional information contact: Program Chair: Karen Xiao, Macro Engineering, KXiao@macroeng.com
Debuting in 2010, the Parts Cleaning Conference is the leading and most trusted manufacturing and industrial parts cleaning forum focused solely on delivering quality technical information in the specialized field of machined parts cleansing. Providing guidance and training to understand the recognized sets of standards for industrial cleaning, every year the Conference showcases industry experts who present educational sessions on the latest and most pressing topics affecting manufacturing facilities today. Discover all that the 2022 Parts Cleaning Conference has to offer!
Presented by Additive Manufacturing Media, Plastics Technology and MoldMaking Technology, the 3D Printing Workshop at IMTS 2024 is a chance for job shops to learn the emerging possibilities for part production via 3D printing and additive manufacturing. First introduced at IMTS 2014, this workshop has helped hundreds of manufacturing professionals expand their additive capabilities.
Get the sprue, runner and gate sizes close to ideal the first time around—without spending a lot of time on extremely complicated formulas.
It doesn’t matter whether you are going to run a flow analysis or not. At some point, you will have to specify an initial sprue, runner and gate size. These sizes are typically nothing more than an educated guess based on someone’s experience, or sizes that simply “look right” to the programmer or designer.
If you run a flow analysis, the software program can tell you if any of these flow channels are too large or too small. Then you tweak their sizes and run the simulation again. If you are not running a flow analysis, the first mold sample can tell you if they are too large or too small. Then you can tweak the steel-safe sizes and sample the mold again. This month’s column will discuss how to get the sprue, runner and gate sizes closer to being ideal the first time around—without spending a lot of time on extremely complicated formulas.
Does the material flow like water or like molasses, or somewhere in-between? That’s actually a loaded question, because it often depends on the processing parameters. The subject of melt viscosity is best left to fellow Plastics Technology columnist, materials expert Mike Sepe, and his 10-part series on Melt Flow Rate Testing. Suffice it to say, the melt-flow index stated on a material data sheet is not a very reliable indication of how viscous a material is or not, because it does not take into account shear thinning. Shear thinning is when the material becomes less viscous due to frictional heat during injection. For example, a polyethylene with a 10 MFI is probably not going to flow the same as a polycarbonate with the same 10 MFI rating.
Fortunately, having just a general idea of the viscosity of the material is sufficient for approximating the initial gate, runner and sprue sizes. If you are not sure how viscous a particular material is, ask someone in the trenches.
The ideal gate size is based on the wall thickness of the part, the volume of the part, the material viscosity under processing conditions, the flow rate of the material going through the gate, and the flow length from the gate to the end of fill. Let’s first discuss a typical rectangular edge gate, which in many ways also applies to lap, chisel, tapered, fan, film, curtain, ring, disk and diaphragm gates. Edge gates have three components: depth, width and land length.
The ideal gate size is based on many variables.
Gate Depth: The gate depth is an extremely critical dimension and is the first dimension that you need to determine. It defines when the material in the gate will freeze. If it is too shallow, it will freeze off too early and prevent additional material from entering the cavity as the molten material cools and shrinks. The part will then be underpacked, which can cause sink, warp, voids, poor surface finish and dimensional inconsistencies.
Determine the gate depth first.
If the gate is too deep, the packing phase will take longer than necessary because you typically wait for the gate to freeze before beginning to retract the screw. Otherwise, the material can flow backwards through the gate and into the massive runner, which can cause a void in the part.
Therefore, determining the gate depth is a balancing act. The chances of finding that sweet spot the first time around is highly unlikely; and unfortunately, the first iteration is often accepted or processed-around during production. It’s best to start off with the gate depth on the shallow side. If the injection pressure is excessively high going through the gate, or if the parts have some sink or burn marks, the depth can be increased because it is “steel safe.”
I typically start with a gate depth of 60% to 70% of the part’s wall thickness at the gate for high-viscosity or highly shear-sensitive materials, such as acrylic or rigid PVC; 50% to 60% of the part’s wall thickness for medium-flow materials; and 40% to 50% for low-viscosity, low-shear-sensitivity materials, such as polyethylene or nylon. Use the lower percentages for thinner-walled parts and the higher percentage for thicker-walled parts, because thicker parts need more time to pack out. Some people suggest making the gate depth relative to the size (actually the volume) of the part. I disagree. The volume of the part should dictate the width of the gate, or the number of gates required—not the depth of the gate.
I once had a part where the geometry was such that the gate depth was 0.200 in., but the gate width was only 0.040 in. In effect, it was a typical edge gate rotated 90°. It left a vertical, rectangular gate scar, as opposed to a horizontal one. The point I am trying to make here is that the narrower dimension will control the gate-freeze time and the wider dimension will control the flow length—regardless of the orientation.
Gate Width: There is an old rule of thumb that says the gate width should be twice the gate depth. I’d like to know who came up with this rule. The decision on how wide to make a gate should be based on the flow length into the cavity, the flow rate through the gate, the flow speed through the gate, and the volume of the part.
I like to think of a gate the same way I think of a vent in a cavity. The vent depth is a relatively fixed value based on the viscosity of the material. The gate depth is a relatively fixed value based on the wall thickness of the part. The vent width is based on how much and how fast the air inside the cavity needs to go out. Similarly, the gate width should be based on how much material needs to go in and how fast. You don’t want a vent, or a gate, to be overly restrictive, which would cause an increase in injection pressure, difficulty in filling the part, high shear, and a host of other problems.
Let’s discuss the importance of how fast material goes through a gate and into a cavity. Any good processor knows that by slowing down the injection velocity you can reduce the amount of shear burning or jetting into a cavity. Reducing the injection velocity obviously reduces the speed of the material going through the gate. It is a common misconception that you should increase the depth of a gate when you have a burning or jetting problem.
While it’s true that making the gate deeper will reduce a burning or jetting problem, so will making the gate wider. When you increase either the gate depth or the gate width, you increase the flow area. The larger the flow area, the slower the speed of the material going through the gate. As previously stated, the gate depth is based on the part’s wall thickness and is a relatively fixed value. The gate width is not a fixed value and is the more logical adjustment. The advantage of increasing the flow area is that you shouldn’t need to reduce the injection velocity to prevent shear burning or jetting, and the higher velocity is often required to fill the part.
Let me put the issue of gate area vs. material speed going through a gate into more perspective. Let’s say you have a single-cavity mold, fed by an edge gate off the primary runner. Let’s assume the molding machine has a 3-in. diam. barrel and you are injecting at 2 in./sec. The material flow rate through the sprue bushing, primary runner and gate is going to be 14.1 in.3/sec.
Table 1 shows what happens to the speed of the material going through four different gate widths. All four gates have the same 0.050-in. depth, but their widths range from 0.100 to 0.800 in. Notice how gate Number 1 has a gate width twice the gate depth, which follows that old rule of thumb. That material will go through the gate at 161 mph. If the material is shear sensitive, you will probably have a burning issue. Every time you double the gate width you cut the speed of the material going through the gate in half. Also notice that the flow rate, or volume of material going into the cavity, never changes regardless of the gate area. Only the speed changes.
With the exception of the size of the gate scar and the difficulty in cutting the runner off the part, there is usually no harm in making a gate wider than necessary. One advantage of a wide gate is that the pressure required to push the material through the gate will decrease as the gate area increases. Sometimes there is more than one exception to every rule. For example, if the gate width is too wide, the speed of the material going through the gate can be so slow that it starts to freeze off before the part is packed out. This condition rarely happens with deep gates filling thick parts, but it is a common problem for very wide gates filling thin parts, such as is the case with fan, film, curtain, ring, disk or diaphragm gates.
For example, let’s say you have a 5-in. diam. cylindrical part with an internal disk gate. A 5-in. diam. part has a circumference of 15.7 in. Now that’s a “wide” gate. In the previous example, where the gate depth was 0.050 in., the flow through this ring gate would be a mere 1 mph. That’s why these types of gates often have to be deeper than anticipated in order to prevent premature freeze-off.
Now let’s take a look at what happens in multi-cavity molds. Let’s stick with the previous example where the flow rate through the sprue bushing was 14.1 in.3/sec. That flow rate of material going through the sprue bushing is cut in half when it splits in half to feed the two primary runner branches. The flow rate splits in half again at the secondary runner branches, and again at the tertiary, quaternary and quinary branches. By the time it gets to the gate, the volumetric flow rate can be extremely small. Table 2 is an example of how the flow rate and the flow speed change based on the number of cavities.
Flow rate and flow speed are cut in half at every runner branch.
The point I am making here is, if you’re injecting 14.1 in.3/sec of material into a mold, don’t think the material is going into each cavity of a multi-cavity mold at the same 14.1 in.3/sec. In fact, for a 32-cavity mold, the flow rate in this example drops down to 0.45 in.3/sec. There is a direct correlation between the number of cavities and the desired material flow rate from the screw. Another reason I am mentioning this is to show you what happens if there is a problem with the mold and you have to shut off a cavity or two. Changing your shot size is not the only process change you should make. You may need to reduce the injection velocity, because the speed and flow rate of material going into the open cavities just increased. That will cause the material viscosity to decrease.
So, how wide should an edge gate be? Since there are so many variables, it is impossible to make a recommendation on how wide to make a gate. A flow analysis is a very useful tool for that determination. You can also determine whether the gate is wide enough during the initial mold trial, by performing a pressure-loss study.
If you had a small, thin part, such as a polypropylene wall anchor, the gate width could be the same size as the gate depth. There wouldn’t be a need to make it any wider, despite what any rule of thumb says. Conversely, when I was a teenager, my father molded a 16 × 24 in. acrylic panel with an edge gate that was 24 in. wide. That is called a “curtain” gate, which is technically just an extremely wide edge gate.
One industry expert recommends using the following formula to approximate the initial gate width:
W = n × ( √A )÷ 30,
where W is the gate width in inches, n is a material constant, and A is the surface area of the cavity in square inches (not the projected area). The material constant n is 0.6 for free-flowing materials, such as PE or PS; 0.7 for slightly more viscous materials, such as acetal or PP; 0.8 for even more viscous materials, such as cellulose acetate; and 0.9 for highly viscous materials, such as rigid PVC.
As an example, let’s say you have a lid for a box that measures 10 × 5 × 2 in. The wall thickness is 0.100 in. and the material is PVC. The surface area of this lid is= (2 × 10 × 2) + (2 × 5 × 2) + (10 × 5) = 110 in2. The gate width should therefore be: W = 0.9 × ( √110) ÷ 30 = 0.314 in. I believe this formula is a little on the conservative side. By that I mean that the gate-width calculations are a little wider than what I would use. Still, it is an excellent “reality check” on what you think the width should be, and 100 times more accurate than the old rule of thumb.
About the Author: Jim Fattori is a third-generation molder with more than 40 years of experience in engineering and project management for custom and captive molders. He is the founder of Injection Mold Consulting LLC in Pennsylvania. Contact: jim@injectionmoldconsulting.com; injectionmoldconsulting.com
Here’s a quick guide to fixing four nettlesome problems in processing PET bottles.
The polymers we work with follow the same principles as the body: the hotter the environment becomes, the less performance we can expect.
Flashing of a part can occur for several reasons—from variations in the process or material to tooling trouble.
With cavity steel or alloy selection there are many variables that can dictate the best option.
There is a well-established relationship between something called the weight-average molecular weight of a polymer and a parameter known as the zero-shear viscosity.
Though often criticized, MFR is a very good gauge of the relative average molecular weight of the polymer. Since molecular weight (MW) is the driving force behind performance in polymers, it turns out to be a very useful number.
To fully appreciate the strengths and weaknesses of the melt-flow-rate (MFR) test it is important to know something about the way the test is performed.
Eye Dropper Molds Plastics Technology covers technical and business Information for Plastics Processors in Injection Molding, Extrusion, Blow Molding, Plastic Additives, Compounding, Plastic Materials, and Resin Pricing. Learn More