Extrusion blow moulding, or EBM, is slightly different from its cousin ISBM. In this case, plastic is pushed out through an aperture around a central axis to create a long, plain plastic tube. The tube is then set into a mould where an air jet is placed into the top opening. Air is blown directly into the plastic tube, pushing the material out into the mould. The plastic takes on the shape of the mould and is ready for decoration. The EBM machines used at Rebhan are 100% electric, providing exact and efficient processing.
- Liquid plastic is pushed out through a nozzle, surrounding a central axis
- The hollow plastic stream is cut at a specific length
- The still-warm plastic tube is set into a mould
- Air is blown into the tube and the plastic takes the shape of the mould
- The resulting container is ready for next steps, like finishing or decorating
The basis of a lot of packaging container manufacturing is ISBM, which stands for injection stretch blow moulding. The process begins with a plastic pre-form that is heated and pushed into a mould by a pin which then ejects pressurized air out of several openings. The material then fills the mould, shaping the container. The majority of ISBM lines use a three-step process that involves injection, moulding, and removal phases. Our machines have an added conditioning step after the initial injection. This phase optimizes the temperature of the preforms allowing optimal material usage and the capacity to create shapes more complex than circular, like ovoidal, square, or polygonal.
- Plastic is pushed into a pre-form mould
- A pre-form is created, which can be stored or shipped
- The pre-form is released
- In the conditioning station the pre-form is heated
- An injection pin pushes the soft pre-form into the mould
- Air is ejected from the pin to expand the material
- The material takes the shape of the mould and is completed
Injection blow moulding is used specifically to create hollow plastic packaging components such as bottles or other containers of smaller volumes. The material to be used is melted such that it is malleable and will accept manipulation. Then it is gathered into a parison (a blob of hot material with a hollow top and interior) and set into the mould in order to be blown out to cover the interior walls. The machines used by Rebhan quickly and efficiently produce individual components, as the heating and cooling times of plastic are short. Almost as soon as the material has been moulded, it can be withdrawn and finished.
- Molten material is injected around a pin
- The pin with the hot material surrounding it is removed from the injector
- The pin and material are set into a mould
- The mould is closed around the pin and the hot material
- Pressurized air is blown through the pin to push the material out into the interior of the mould
- The mould is opened and the moulded component and pin removed
- A finishing bolt travels along the pin to remove it from the component
- The finished piece of packaging can move on to be cleaned up and decorated
COEX, or co-extrusion, is not a container manufacturing technique, it is used in material preparation. Plastics undergo the same extrusion process as in EBM where plastic is pushed out an aperture around a central axis, but in this case two or more materials are extruded simultaneously to a create multi-layer material that may then be used in another manufacturing process. The multiple layers ensure the right combination of properties so that the final packaging item has the proper mix of tensile strength, barrier properties, pliability, and weight. COEX is often used to create full bottles that can be used directly or decorated. Each machine Rebhan uses offers multi-cardioid heads that can handle high molecular weights, meaning several material layers can be incorporated into the process for different barriers.
- Different polymers are injected sequentially into the extrusion chamber, creating layers
- The resulting mass is pushed out around a central axis to create a multi-layer tube
- The tube can be used as is for several applications or as part of an EBM lines
Modern techniques in injection moulding (IM) mean a mould is created, it is filled with molten plastic, and after it has cooled sufficiently, the mould is opened and the finished piece is withdrawn and tidied. Rebhan's machines offer spindle drives that are direct-acting and ensure optimal repeat accuracy and part quality. They're also very clean as they feature liquid-cooled, encapsulated servo-electric drives and power recovery during braking.
- Liquid plastic is pushed out through a high pressure nozzle, with a screw plunger that assists the process
- The injected liquid takes up all the space inside the mould
- The injection rod is removed and the mould is closed
- The mould is opened to reveal the finished product
- The piece of packaging is removed to be cleaned, trimmed, and decorated
Decorating a piece of packaging is an important process. The right look and feel is important to consumer recognition, brand equity and sales. To ensure a brand's packaging at it’s best, we offer all state-of-the-art decoration techniques in-house.
We are experienced in silk-screening, hot stamping, lacquering, metallization.
Bespoke packaging is unique because of the shape in combination with decoration. Decorating standard packaging will make it pop on the shelf, drawing consumer eyes and increasing the odds of purchase. The right decoration will ensure that your standard packaging product will also be truly special.
Decoration we offer
This technique involves using a permeable screen that has zones blocked off so that ink can be transferred to a surface, with numerous colours being mixed or applied in layers to create just the right look. All sorts of different types of shapes and images can be transferred efficiently with very precise edges. Silk-screening has evolved significantly over the last few decades with regard to accuracy and velocity since its introduction as an industrial decoration technique.
Hot-stamping occurs in a totally dry printing environment where foils are applied to surfaces using high temperatures. Temperatures are precisely set to effect the transfer without causing any damage to the surface where it is being applied. This technique is most often used with temperature-resistant metallic foils in different colours, such as gold or silver, though many modern foils can be applied in order to achieve a specific effect, such as holographs or textures. Rebhan also offers a unique wide area hot-stamping technique where the contour of the packaging is taken into account allowing for an end result with perfect geometry.
There is a difference between full metal components and the metallization of another material. In this case, we offer the ability to coat our plastic items in a metal finish that offers the appearance of a full metal piece of packaging without the added weight that solid metal normally involves, even light weight aluminum. Each component undergoes a precise coating process where the thickness of the metallization is strictly monitored, to ensure an even coating and a proper look and feel.
This technique applies surface coatings to the packaging. All our lacquers are water-based, which are much less harmful to the environment. The lacquer may be shiny, producing a glossy effect which is bright and eye-catching; it may be dull, which leaves a matte effect that's elegant and cool; it may also be a gradient, which is a visual transformation where one colour merges into another without noticeable banding. Stone-optic lacquering gives components the visual appearance of rock. Finally soft-touch lacquering adds a smooth and velvety feel to containers, providing a more pleasant consumer experience.