Hybrid production chains have been increasingly in the spotlight in recent years. This also applies to the combination of conventional manufacturing and additive processes in tool construction. With the example of an injection molding tool, it is shown how mold inserts produced by additive manufacturing can greatly shorten cycle times, and thereby significantly reduce unit costs. The important thing is to find a suitable combination of processes from the variety available.

Additive Manufacturing and Hybrid Molds in Combination with Conventional Machining

Spritzgießen

Kunststoffverarbeitung: Verfahren

HSC- / HPC-Bearbeitung

Spanende Verfahren

Werkzeugkonstruktion

Dienstleistungen

Werkzeug-, Formen- und Modellbau

Spritzgießwerkzeuge

Kunststoffverarbeitung: Maschinen und Komponenten

Werkzeuge für die Kunststoffverarbeitung

Additive Fertigung

Anlagen Additive Fertigung / 3D-Druck, Metall

Anlagen für die Additive Fertigung

The Potential of Redesign and  Part Consolidation

At the 2019 K fair, Arburg and Simcon showcased a filling process proceeding in real-time, as a 3D animation, on the display of a machine control panel, for an example of sunglasses, made of PA12. All that was needed to prepare this, was to load the simulation model, as well as the geometry of the part, directly onto the machine controls. This sounds almost too easy to be true. Right?

Interview with Eberhard Duffner and Paul F. Filz by the Magazine Kunststoffe

Doriat, Clemens, Dr.

Spritzgießsimulation

Software

Simulation

Interview

The toolmaker Siebenwurst uses injection molding simulation to optimize part design and production processes in its routine workflows. Among other things, Simcon’s software ensures the quality and dimensional accuracy of the plastic frame for the first series-produced injection molded e-bike.

Controlling Complex Development and Manufacturing Processes, Using Simulation

Composite-Halbzeuge

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

Verbundwerkstoffe / Werkstoffverbunde

Kunststoff Werkstoffe

A Bike Frame from an Injection  Molding Machine

Plastics processors have a wide range of colors at their disposal to color their products. Choosing the right color can ultimately be the key to success. But colors are just as subject to trends as materials and designs. Kunststoffe asked manufacturers of pigments, masterbatches, and colorants which colors would be particularly popular in the coming year.

Trend Report on the Coloration of Plastics

Pigmente

Additive

Pigmente, bunt

Masterbatches

Farbstoffe und Pigmente

Kunststoffe

Photonik

Optik

Streifinger, Florian

Recycling

Umweltmanagement

Farbkonzentrate (Batches)

Farbstoffe

Effektpigmente

Kunststoff-Recycling

Kunststoff-Aufbereitung

Farben, flüssig

What Will Be the Color of 2021?

Susanne Schröder will become editor-in-chief of the magazines Kunststoffe and Kunststoffe international on December 1, 2020. The current editor-in-chief Dr. Karlhorst Klotz will leave the company by mutual agreement.

Werkzeuge für Leichtbauwerkstoffe

Präzisionswerkzeuge

Tiefziehwerkzeug

Werkzeugüberwachung

Toolmanagement

Werkzeugwechselsysteme, Spritzgieß

Werkzeug- und Formenbau

Modulare Werkzeugsysteme

Absaugungen für Werkzeugmaschinen

Betriebsausrüstung / Betriebsmittel

Absaugvorrichtungen

Fluorkunststoffe

Thermoplaste

Werkzeugverwaltungssoftware

Prüfen von Kunststoffen

Messtechnik

Biokunststoffe

Presswerkzeuge, Kunststoff

Werkzeugreinigung, Kunststoffe

Standardkunststoffe

Kunststoffverarbeitung

Lohnfertigung

Technische Kunststoffe

Füllstoffe für Kunststoffe

Kunststoff

Bauwesen

Baustoffe

Kunststoffhandel

Handel

Betriebstechnik für Kunststoffverarbeitung (Peripherie)

Kunststofffasern

Verstärkungsstoffe

Hochleistungskunststoffe

Qualitätssicherung Kunststoff

Qualitätssicherung

Change in the Chief Editorial Office of Kunststoffe

A tool logbook on paper is often not to hand just when you need it most. Or it is incomplete, since it is time consuming to keep the information up to date. A cloud-independent, electronic tool log, which is directly integrated into the tool could make all the relevant data available directly.

The Electronic Tool Logbook as a Combination of Operating Manual and Check List

Werkzeuginnendrucksensoren

Sensoren / Messwertaufnehmer

Messdatenerfassung und -verarbeitung

Papierlose QM-Dokumentation

Qualitätsmanagement

Dokumentationsmanagement

Mobile Datenerfassung

Logistik

Lagertechnik

Digitale Transformation

Wirtschaft

Innovationen und neue Technologie

Fernwartung / Ferndiagnose

Instandhaltung

Dokumentenmanagement, CAQ

Data Management at the Tool

At K 2019, the metrology experts at Kistler AG, Winterthur, Switzerland, showed how artificial intelligence will pave the way for the smart factory. ComoNeoPredict, a module of the ComoNeo process monitoring system, allows model-based prediction of the desired part quality based on the cavity pressure and temperature profiles. 

Kistler Puts Artificial Intelligence into Plastics Processing 

Networked Production with an Adaptive System 

An electric valve gate cylinder, which moves the valve pin directly, and in so doing sits on the manifold, is as compact and easy to maintain as conventional hydraulic cylinders, which would represent combining the best of both worlds. So does this work? 

Introduction of New Electric Valve Gate Cylinder 

Normalien und Heißkanaltechnik

Compact User-Friendly Electric Valve Direct Drive 

During this year’s pandemic, maintaining supply capability has become a key necessity among processors. Closer involvement of suppliers is only logical in these circumstances. In toolmaking, new challenges are emerging for services related to molds.

The Advantages of a Network for Global Qualification for Injection Molding

Erstbemusterung, Erstmusterprüfbericht

Werkzeugbau

Inline- / Online-Messsysteme

Fast and Effective Start of Production

A solution, which is unique in Europe, significantly increases productivity and comprises the production from a 12+12 stack mold with fully automated in-mold labeling and removal with visual 100 % inspection of the parts.

Fully Automated Production Line with Stack Mold and In-Mold Labeling

Heißkanalsysteme

Komponenten für die Kunststoffverarbeitung

Award-Winning Packaging Solution Increases Productivity

In the production of plastic parts for the medical and pharmaceutical industry, the requirements for cleanroom environments are becoming increasingly stringent. In this area, not only the demand for all-electric injection molding machines is increasing. There is also an increasing use of electric drives for the implementation of mold movements, which meet the high requirements for cleanliness and reliability.

Electrical Drives in Injection Molds

Elektrische Antriebe

Antriebe

Mess- / Regel- und Prozessleittechnik

Prozessautomation

Mess-, Steuer- und Regelgeräte

Medizintechnik

Reinraumsysteme / -technik

Medizinprodukte

Mold Technology

Increasing demands on component functionality and the need for efficient manufacturing processes are keeping multi-component injection molding squarely in the focus of plastics processing. Not all materials can be processed reliably in the desired combination. The new InMould-Plasma process, which is fully integrated into the injection molding process, facilitates more-efficient production and paves the way for completely new material combinations.

More Material Combinations,  Lower Costs

Thermoplastische Elastomere

Mehrkomponenten-Spritzgießen

Plasmabehandlung

Oberflächentechnik

Reinigen und Vorbehandeln

Dichtungsschäumen

Schäumen / Reaktive Verarbeitung

InMould-Plasma Streamlines the 2-Component Process and Expands  the Material Spectrum

Mold breathing provides useful information about the processes that occur in the mold and the cavity. Mold-maker Schneider Form and injection molding machine-maker Engel have recognized the potential which this process variable offers and have worked intensively on it for several years, albeit by adopting different approaches. They recently carried out joint tests on bumper molds using a two-platen injection molding machine with a clamping force of 40,000 kN and then swapped experiences.

Comparative Methods for Determining Mold Breathing

Energiemanagement / Smart Home

Installationstechnik

Industrie 4.0 für die Kunststoffverarbeitung

Industrie 4.0

Druck- / Kraftsensoren

Spritzgießmaschinen

Using Breathing Signals for  Process Optimization

The newly developed Compactcube mold system from Foboha can be used on slightly modified standard machines in the low to medium clamping force range. This means that the advantages of cube mold technology are now also available for applications with smaller production volumes.

Compactcube Reduces Initial Capital Outlay and Maintenance Requirements

New Application Areas for Cube Molds on Standard Machines

Ambient lighting has captured the car interior – and facilitated orientation for the passengers. There is no need for anyone to fumble for the seat belt buckle in the dark in the Audi A7, as an integrated light guide shows the way. Kunststoff Helmbrechts produces the 3-component part and also developed the tool concept. The trick:  a so-called twin-turn tool which rotates on both sides. The company was awarded the GKV TecPart Innovation Prize for it at the K 2019.

Twin-Turn Tool Provides Solution to Production Problem with a Double Turn

Polycarbonat

KFZ-Zulieferer

Runway Lights for the Seat Belt

Exciting Design instead of  Exciting Manufacturing

A 3D-Printed Nozzle and Modified Dosing Method Deliver Reproducible Marbling  in a Robust Process

Marbling is often a real eye-catcher in plastic components. However, the effect is difficult to create and there are some pitfalls when it comes to reproducibility. Novel nozzles for injection molding machines in combination with a special dosing technology allow marbled molded parts to be produced far more easily in a much more robust process.

Marbled molded parts have been around since the early days of plastics when, for example, combs or buttons bearing a marbled pattern were produced. In some cases, the marbling happened unintentionally because homogenization in the plunger injection molding machine had still not been perfected.

With the advent of screw injection molding machines, not only plasticizing capacity has increased, but above all significantly better melt homogenization has become possible, paving the way for colored molded parts without any color streaks on their surfaces. In addition, mixing elements are sometimes deliberately installed in injection units in order that mixtures of uncolored pellets and masterbatches may be converted into streak-free molded parts.

Now, marbling effects are created either mechanically with the aid of special marbling screws or by means of two-component injection molding machines. In the latter, two molding compounds of different color are injected into one cavity, usually by sequentially opening and closing valves which are located either inside the mold or between the machine nozzle and the mold. However, the production of reproducibly marbled parts in two-component injection molding machines is relatively costly, as two injection units are required and have to be operated.

Since parts with marbled surfaces often look very attractive and unique, they are still in demand, even though the manufacturing process is complex. A process by which they might be produced reliably and reproducibly without major technical outlay would therefore appear desirable. An ability to specifically influence the marbling patterns would also give designers additional freedom over the visual design. BASF SE, Ludwigshafen, Germany, has developed one such process that allows marbled molded parts to be produced with little outlay.

Marbled molded parts typically have patterned visible surfaces bearing such effects as color shading, color streaks, lines and texture. The formation of the effect varies with the proportions of the different colors and the base color of the part. Although marbled molded parts manufactured in a production run are not absolutely identical, they look essentially very similar. Some of the patterns achieved with this technology are reminiscent of the appearance of natural materials, such as marble or wood. For high-contrast, clearly defined marbling patterns to be achieved, the admixed color batch must not be completely homogenized. At the same time, though, all the pellets must be completely melted and homogenized in order that the finished molded parts may possess the specified properties.

Initial trials conducted by BASF on molded parts revealed that the patterns differed according to whether they were produced with a needle-valve or an open nozzle. The number of flights of a screw tip was even discernible on the parts’ surfaces. The patterns arise from the separating and merging of melt flows in the channels of the plasticizing unit. This insight prompted a decision to rethink the nozzle of the injection molding machine and to employ different melt channel geometries in the nozzle cap. For this purpose, a recess for accommodating interchangeable inserts was created in a standard nozzle cap. As a result, the channel geometry in the nozzle can be changed to create all manner of patterns (Fig. 1). A symmetrical arrangement of straight channels, for example, results in symmetrical patterns.

Marbling proves to be particularly effective in the case of flat molded parts. But it is also possible to create three-dimensional articles that possess highly attractive marbled surfaces (Fig. 2). The marbling pattern is determined by the nozzle design and the mold’s gating system and the subsequent spreading of the melt. Thus, it is also influenced by the location of the injection point and the filling behavior of the melt in the direction of flow during injection into the cavity. Figure 1 shows the many possibilities for symmetrical parts that are gated centrally. Attractive patterns may also be achieved by using molds equipped with hot runners and tunnel gates (Fig. 3). The resulting molded parts are not centrally gated and so the pattern of marbling streaks is completely different from those shown in Figure 1.

Additive manufacturing processes offer a very high degree of design freedom over the production of nozzle inserts. In particular, they can be used to create channel geometries that cause the melt to swirl as it flows into the mold (Fig. 4). This affords a way of producing mirror-image patterns and rotationally symmetrical patterns. The swirling of the melt is clearly visible in the pattern shown in the Title figure and Figure 1. Such patterns were previously not feasible with conventional processes.

The nozzles can be produced by additive processes such as laser welding and layer fusion processes, such as fused deposition modeling (FDM) and fused filament fabrication (FFF). Catamold pellets from BASF, for example, can be used to manufacture the nozzle and nozzle inserts. Here, a filament made of Ultraform, a polyoxymethylene (POM) from BASF that contains metal powder, is printed by the FFF method, followed by debinding and sintering. The final step of the process entails adjustment work such as fitting the printed insert into the nozzle cap.

The marbled parts can be produced on standard injection molding machines fitted with just one plasticizing unit. All that is necessary is to synchronize the dosing of the material with the injection molding cycle. The materials are fed as usual into the existing feed opening in the hopper area of the plasticizing barrel. Conventional, only slightly modified dosing devices fitted with two hoppers are used (supplied, e. g., by motan GmbH, Konstanz, Germany). The base material, which is usually mixed with a color batch, is supplied in the conventional way, while a further high-contrast color batch, e. g. black, is fed into the plasticizing unit separately with great precision.

As mentioned, the process can be carried out on commercial injection molding machines without the need for specialized equipment. Ideally, the sole requirement on the injection unit is that it meets certain specifications, e. g. a low ratio of shot volume to barrel size. The injection molding process itself is not different from usual, and the process parameters are normally the same. The various influencing factors on marbling are summarized in Table 1.

Correct dosing and the combination of “contrast” batches and coloring component are also important in the production of marbled molded parts. The choice of color combination is key to a successful marbling outcome. If the contrast batch is overdosed, the coloring component very soon loses its brilliance.

Ultimately, mold design, part geometry and the nozzle used in the machine and in the hot runner determine the resulting pattern. In the course of conducting its development work, BASF tested molds fitted with conventional sprues as well as with hot runners. In both cases, attractive patterns were obtained. The finish of the mold cavity’s surface has an additional influence on the patterns’ appearance. Whereas highly polished surfaces accentuate the contrasts intensely, textured surfaces lead to an unobtrusive, matt appearance (Fig. 5), as is also the case when glass fiber-reinforced materials are processed.

Marbled molded parts are chiefly used for decorative purposes in the consumer goods sector. They serve as household objects, e.  g. bowls, plates, cups, handles, and covers, as well as laptop lids and smartphone covers, as fashion accessories, e. g. buttons, as decorative elements in vehicle interiors, e. g. caps and covers, and as parts for toys. For many of these applications, the polymers should at least have a food contact (FC) classification, as is the case for Ultradur B4520 FC, a polybutylene terephthalate (PBT) supplied by BASF. In contrast, various polyamides (PA) such as the Ultramid Deep Gloss or Ultramid Vision family from BASF are suitable for automotive interiors.

With the aid of the process presented here, it is possible to reproducibly manufacture marbled molded parts in different patterns on standard injection molding machines fitted with novel nozzle inserts and special dosing technology. Aside from PBT and PA, the process lends itself to other thermoplastics that are currently undergoing testing. BASF offers its customers not only suitability tests on existing molds and machines, but also support with nozzle design and 3D printing of pilot series, with the selection of materials and colorants and process control, as well as assistance with implementation into mass production. Mold provings can be carried out on the converter’s premises or at any time in BASF SE’s pilot plant on the customer’s own molds.

BASF Aktiengesellschaft  

www.basf-ag.de

Ausgabenartikel

Marbling leads to attractively designed molded plastic parts, but is not so easy to implement in production

Table 1. Influencing factors on the marbling

Fig. 1. All kinds of marbling effects can be achieved, depending on the channel geometry employed

Fig. 2. Not only flat molded parts but also attractive three-dimensional articles can be produced with a marbling effect. Correct dosing and the combination of “contrast” batches and coloring component during production are also important

Fig. 3. Molds fitted with hot runners and tunnel sprues can be used to produce very attractive patterns. As these molds are  not injected from a central point, the marbling streaks vary in their pattern 

Fig. 4. Nozzle inserts made by 3D printing offer designers huge freedom of design. Flow-optimized channel geometries in the nozzles can be used to make the melt swirl on its way into the mold. This also supports the creation of rotationally symmetrical patterns

Fig. 5. The surface finish of the mold cavity influences the appearance of the samples.  Highly polished surfaces strongly accentuate contrasts. Textured surfaces leads to a matt appearance

BASF - Hauptartikel

Dr. Reinhard Jakobi is Head of Performance Materials Processing at BASF SE, Ludwigshafen, Germany; <a href="mailto:Reinhard.jakobi@basf.com">Reinhard.jakobi@basf.com</a>;

Angelika Homes and Susanne Zeiher work in the Performance Materials Processing Department.