Injection and blow moulding presses use plastic granules loaded from a hopper into a closed auger. They pass through a heater to be melted and forced into a mould. While this guidance has not been updated to reflect current work health and safety legislation the Health and Safety at Work Act and regulations , it may still contain relevant information and practices to keep workers and others healthy and safe. Please read this guidance in conjunction with all relevant industry standards that apply to you as a PCBU. This guidance will be progressively reviewed and either updated, replaced with other guidance, or revoked.
This excess plastic Tia slip n slide then recycled to create new moldings. As is possible with all Foamcore parts, the combination of skin thickness and foam core density can be optimized to meet weight-reduction and impact-performance goals. Foamcore cycle times Blow molding process figure similar to that of a standard blow-molded product. This process also increases the strength to be ideal for filling with carbonated drinks. Like this presentation? A at Chemical Engineering Specialist. No increase in barrier strength as the material is not biaxially stretched. When guards are open, there MUST be a second option to Blow molding process figure off power. Many functional designs are greatly enhanced by the inclusion of compression-molded tabs, locks or mounting surfaces.
Pirates dvd sex. D. Exterior Surface (Mold Cavity) Design
The proof is found in the more consistent container diameter of Fasti containers, which is not associated with wall thickness. An aluminum mold with a proces in the shape of the desired bottle is clamped around the parison clamping the bottom shut; the parison is then cut off mmolding the figjre. The stretches in both primary directions molving also obtained from the first simulation blow molding. NY: Marcel Dekker, Inc. The answer lies in the uniformity of the material distribution in the oriented portions of the finished bottle. Once the material has been stretched past its natural stretch ratio NSR Da dramatic increase in force is Blow molding process figure for additional stretching to occur. The manufacturing process was started up. This may explain the large variance percent crystallinity between container samples shown in Table Dimensional stability of the container is critical to maintain tolerances for the filling operations in Blow molding process figure of volume as well as dimensions in the finish area to allow the closure to work well with the container. This is because a warm mold tends to promote relaxation of internal stress. The most statistically significant points those with p-values less than 0. Number of Parts Produced per Hour.
The Custom-Pak blow molding design guide provides you with basic design tools for making engineered blow molded parts.
- Blow Moulded Water Storage Tanks.
- Blow molding is a process in which plastic hollow parts are formed.
- Blow molding BrE moulding is a specific manufacturing process by which hollow plastic parts are formed and can be joined together.
- Biaxial orientation provides enhanced physical properties, clarity, and gas barrier properties, which are all important in products such as bottles for carbonated beverages.
Figure 2: Production stages of expanded polyolefin particle foams. Figure 3: Foamcore tool details with fill-gun. Figure 9: Foamcore cross-section with tack-off. Figure Foamcore part design guidelines. Figure Flexural strength property comparison. Figure Foamcore thermal insulation performance. W ith emphasis on weight reduction throughout the transportation industry, there is a renewed effort to remove as much mass as possible to improve vehicle performance.
JSP has developed and optimized a blow-molding process that combines traditional blow molding with an injection-molded particle foam core. This process, called Foamcore, utilizes traditional blow-molding equipment combined with a particle foam injection unit to produce a composite blow-molded part with a solid foam core.
Multiple polymers can also be used, including polypropylene PP , polyethylene PE , polystyrene PS , and others, for both skin and core materials. This paper will describe recent advancements of this technology, and how they allow for improved mechanical properties to be realized in the area of transportation applications for structural and semi-structural components. Other features discussed include improvements in thermal insulation and sound abatement, as well as recyclability and end-of-life requirements.
This technology allows the production of single-layer traditional blow-molded parts with a foamed inner core in a single shot. Traditional extrusion blow molding begins with extruding the base resin to form a parison, which is drawn down between two mold cavities.
The parison is then clamped between the closed mold cavities, and air is blown into it via one or more blows to form the cavity. The action of the air, with the help of external vacuum assist on select portions of the tool , allows for the formation of the part.
Once the plastic has cooled and hardened, the mold opens up and the part is ejected. Blow molding can consist of a single layer or multiple layers of different resins or combinations of resin blends.
In the case of structural blow molding, a single layer is generally used. In order to control the structural rigidity of the blow-molded part, the parison thickness can be controlled, resulting in a controlled part thickness for additional support.
Resin fillers can also be used. The Foamcore process uses traditional extrusion blow molding technology using the accumulator method to drawn down the parison.
After the mold is closed and the parison is blown to form the cavity, the Foamcore technology is engaged. The basic steps are as follows: 1 blow molding, 2 puncturing cavity, 3 filling bead foam, 4 steaming, 5 cooling, and 6 ejection. Figure 1 illustrates the basic steps of the Foamcore process. All of these steps take place as the tool is closed using a standard blow-molding tool and press configuration, along with standard blow-molding resins including PS, PP neat, talc filled, glass filled, etc.
While these resins function as the outer layer of the traditional blow-molded part, the inner cavities are injected and filled with expanded polystyrene EPS , expanded polypropylene EPP , or expanded polyethylene EPE.
By combining these two technologies, the result is the ability to produce a much lighter structural product with better thermal insulation and sound insulation values. Applications include transportation automotive, agricultural, aviation , construction, sporting goods, and any application where traditional blow-molding parts require additional structural support. Additional benefits include simplicity of design no complicated tack-offs required , cost reduction from component consolidation , weight reduction structural core allows for thinner skin , and of course, insulation and acoustical benefits.
The level of structural support can be optimized by increasing or decreasing the density of the particle foam used inside the part. Expanded polystyrene particle foams can also be produced, whereby a resin particle is secondarily expanded using either an inert or VOC gas. While many polyolefin particle foams can be produced using either inert gas or VOCs, all polyolefin particle foams produced by JSP are expanded using an inert gas batch expansion process.
Figure 2 contains a basic diagram showing the production stages of expanded polyolefin particle foams. In addition to the blow-molding tool modification, additional secondary equipment is required to properly fill and steam fuse the particle foam inside the blow-molded cavity. This secondary equipment consists of a pressurized particle-foam fill system capable of 4 bar pressure , source of steam capable of 4 bar pressure , source of air 6 bar pressure , and vacuum.
Foamcore technology combines the machine capabilities of standard blow-molding and steam-chest compression molding. This system design can be made portable so that it can be readily integrated into multiple blow-molding machines are needed.
Figure 3 shows the details of the fill gun as viewed from inside the mold cavity. The left picture shows the fill-gun tip engaged into the cavity, which is how the formed parison is initially punctured to allow for the particle foam to be injected into the cavity. It remains in this position during the remaining cycle steps. First, they deliver air to the cavity to assist the blowing or forming of the parison, and maintain cavity pressure.
Second, they deliver the steam necessary to fuse together the particle foam inside the cavity. Third, they draw vacuum to evacuate the cavity and remove the steam condensate during and after the steaming step. They are capable of maintaining the vacuum during the cooling step, which serves to remove excess heat from the inside part, thus minimizing the cooling time and possibly reducing cycle time. Note the shape of the probe tip and the integrated vents around the circumference of the probe through which the air and steam flow, and through which the vacuum is drawn.
The four steps shown are typical for all Foamcore parts. Foamcore cycle times are similar to that of a standard blow-molded product. The resulting molded Foamcore part is a hybrid combination of a blow molding and a particle-foam steam-chest compression molding.
When converting a traditional blow-molded part to a Foamcore part, it is important to consider the part design and functionality. A single side of the tool can be modified without changing the overall part configuration. In the case of a load floor or automotive seat back, the back side of the part would be used. Note the spacing of both features.
The benefit of the Foamcore technology is the structural nature of the molded part configuration. The end result is a predictable, void-free, cross-sectional combination of skin and foam core. Note the fusion of the EPP particle foam, and the particle foam-to-skin bonding as well. As was mentioned earlier in this paper, the Foamcore process allows for a structural part to be designed and produced without numerous complex tack-offs.
However, if tack-offs are required, they can be accommodated with the Foamcore process. Figure 9 shows a Foamcore cross-section with a tack-off. While traditional blow-molded parts can be converted to the Foamcore technology, it is important to understand the design requirements necessary to take advantage of the benefits of Foamcore.
In addition to the obvious choices of skin material and foam core material, the Foamcore technology can be optimized by following a set of design guidelines.
Figure 10 shows the basics of Foamcore part design and provides a guideline for optimal particle foam density, skin thickness, part thickness, product size, radii recommendations, and tool shrinkage shown for PP skin and EPP core materials. Depending on the specific blow-molded part design, there are obvious trade-offs when converting to Foamcore technology. Ideally, the advantages and benefits of Foamcore technology are best utilized when the part is designed with the use of Foamcore in mind.
As was mentioned earlier in the paper, there are a number of benefits to using Foamcore, in addition to the obvious weight savings and structural improvement. These include acoustic performance, flexural strength, and thermal insulation. The acoustic benefits come from the fact that traditional blow-molded parts, being hollow, tend to resonate sound and in many cases, can amplify sound, creating a need for noise abatement and the use of a secondary acoustic barrier or other means of reducing the noise.
With Foamcore, the internal molded particle foam core acts to absorb sound as well as dampen and isolate sound energy, preventing it from being transmitted across the molded part. This is particularly useful in a variety of automotive and rail parts such as seat backs, load floors, and other structural parts.
The benefit of the foam core from a flexural strength standpoint is also important. The foam core acts to minimize bending across the entire part shape. Depending on the force applied, the improvement of the Foamcore technology ranges from two to ten times that of a traditional blow-molded cross-section.
Of course, the performance can be further optimized by changing the skin thickness and the foam core density. This can be particularly useful in an application like a seat back, where OEM and platform-specific performance requirements including seat-back retention, ECE R17 intrusion performance, etc.
The thermal insulation benefits of Foamcore are due to the fact that the particle foam offers good insulation properties. Figure 12 shows the thermal conductivity of a Foamcore part using EPP particle foam vs.
The improvement in insulation value of the Foamcore part is close to four times that of the traditional blow-molded part. This benefit could be used to improve the insulation of a number of transportation components in automotive, rail, or aviation applications, and prevent the use of secondary insulation, which adds both cost and weight. The benefits of using Foamcore technology in transportation applications are many. Some key benefits include weight reduction, part consolidation, structural Improvement, design simplification no tack-off, cores, etc.
Any combination of the above benefits can result in cost savings as well. Depending on the application and performance requirements, Foamcore technology can be optimized to solve a number of design-related issues, all while maintaining the original part configuration.
It is also possible to insert mold fasteners, brackets, and other components using the Foamcore technology. The insert molding of carpet or other coverings is also possible, as is the case with traditional blow-molding technology.
Figure 13 shows an application where the Foamcore technology is used for a seat back. Figure 14 shows the exposed side of the same part as mounted in the vehicle. This configuration is typical of an automotive seat back, as well as a load floor and other structural panels used in transportation applications.
In addition to structural panel applications like seat backs and load floors, Foamcore technology can also be used for applications requiring a combination of structural and impact performance. Figure 15 shows an application where Foamcore technology was used for a truck bumper. Note the overall configuration and the cross-section. This particular application consolidated the bumper cover with the energy absorber to produce an integrated structural-core bumper system.
Figure 16 shows a close-up of the cross-section. As is possible with all Foamcore parts, the combination of skin thickness and foam core density can be optimized to meet weight-reduction and impact-performance goals. Much as blow-molding resins are available with different additives fire retardants, colorants, anti-stats, etc. Materials like EPP are available with fire retardants for use in aviation and rail transportation applications, so that stringent flammability specs can be met.
Other benefits of the Foamcore technology include the closed-cell nature of expanded particle foam, which allows for water-proof solutions where traditional blow-molded designs may be prone to fail with any intrusion or damage to the skin. The Foamcore technology can be readily adapted to existing blow-molded processes with existing tooling and equipment, so that existing designs can be optimized for both performance and weight savings.
The ability to optimize skin thickness along with particle foam density allows for further part optimization. Since the particle foam material is strictly internal, all trimmed offal remains the common skin resin.
Containers were manufactured by the two different manufacturing methods: Fasti Cold Air blow and Conventional blow. As the preform is not released during the entire process the preform wall thickness can be shaped to allow even wall thickness when blowing rectangular and non-round shapes. The air is forced into the container, where it remains during the entire blow-cycle and is allowed to escape during the exhaust cycle. Types of EBM equipment may be categorized as follows:. Blow Valve Blocks. Thickness in. Effect of Decreased Crystallinity in Polymers Hernandez et al, As is evident in the table, a reduction in crystallinity can have significant effects on bottle performance.
Blow molding process figure. Introduction – Blow Molding
Blow Molding Design Guide – Custom-Pak, Inc.
Injection and blow moulding presses use plastic granules loaded from a hopper into a closed auger. They pass through a heater to be melted and forced into a mould. While this guidance has not been updated to reflect current work health and safety legislation the Health and Safety at Work Act and regulations , it may still contain relevant information and practices to keep workers and others healthy and safe.
Please read this guidance in conjunction with all relevant industry standards that apply to you as a PCBU. This guidance will be progressively reviewed and either updated, replaced with other guidance, or revoked. The moving part of the mould is forced against the fixed part by a hydraulic ram with several tonnes of force. Molten plastic is shaped into a hollow tube, which is blown into the shape of a mould, for example a bottle.
The mould is held closed during plastic injection and cooling. It is forced open by the hydraulic ram and the moulded item is taken out for further processing. Blow moulders often have machinery associated with them to handle formed products. This additional machinery presents hazards that require identification and guarding. Plastic is forced into moulds under high pressure.
Leakage between the auger and the mould is likely to squirt out jets of molten plastic. A safe noise level over an eight hour day is 85dB A. An injection and blow moulding press may exceed this noise intensity. Instructions MUST be available in a language understood by the operators. Material safety data sheets MSDSs should be made available. Presses MUST meet original specification.
If additional safeguards are required, they MUST be added by a competent technician working to recognised standards. Commissioning of hazardous substance location or transit depot. If someone has been seriously injured or become seriously ill as a result of work, you must notify us. Not sure if you need to notify us? If you're unsure of what needs to be notified please read our guide What events need to be notified?
Machinery Notify WorkSafe. LIFT loads in manageable quantities. USE mechanical aids when necessary. USE pneumatic conveyors. FIX guards where possible to prevent reaching into the auger. KEEP interlocked guards safely maintained. USE mesh to prevent reaching through hoppers. Crush injuries to anyone caught in a decreasing gap. Automatically PUSH moulded components from the mould, onto a belt conveyor or into a bin for collection. USE mechanical aids for lifting, when appropriate. Burns from touching the auger cover or being hit by molten plastic Inhaling toxic fumes — breathing problems, lung damage.
When heating granules, USE temperatures low enough to avoid formation of toxic vapours. USE respiratory protection. Crush injuries Bruising Fractures. USE dual channel interlocks to stop mould parts moving while guards are open. USE mesh within the hopper, or by high-sided hoppers, to prevent reach to the moving auger. Eye irritation or damage Breathing problems Lung damage or cancer Worsening of existing health problems Risk of explosion or fire.
KEEP fire extinguishers nearby, and ensure operators know how to use them. Trapping or crushing injuries Burns Bruising. KEEP up-to-date housekeeping procedures. KEEP the area around machines clear of slip and trip hazards. When guards are open, there MUST be a second option to shut off power. USE the correct electrical rated equipment.
KEEP guard interlocks safely maintained. Share on Facebook. Share on Twitter. Share on LinkedIn. Share by Email. Last updated 7 September Back to top. Search Worksafe Submit Search.
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