Our company produces plastic parts in a thermoplastic rotation process which is also called rotational molding or roto mold. In this process we not only produce our own product range of container for liquids and bulk goods, collection trays and containers but also articles according to customer demands such as tanks, containers, furniture, lighting, coverages and cover panels. Because of our roto mold process we are able to produce seamless plastic hollow parts with a volume range of 0,1 to 40.000liter with low tool costs and a variety of thermoplastic plastics. Thereby geometric specialties such as a complex forming with many openings and throughout connections, threads and metal inserts but also complex re-entrant angles are not an obstacle for our experienced team. Customers worldwide value the high quality and good visual appearance of containers made in the ARICON production. The economic success of the ARICON GmbH is based on long-term thinking, responsible handling and economical as well as the social sustainability. Those are factors that are represented in the product through robustness, impact resistance, long-living and a one hundred percent recyclability. During thermoplastic molding even geometrical specialties such as re-entrant angles are no difficulty. We support you during the whole production process. Starting with the first ideas and a technical consulting to construction and decisions about the material, surface and form as well as specialties such as re-entrant angles to the series production, montaging and packing of the seamless hollow plastic parts.

Why is the process called rotational molding?

The process is called thermoplastic rotational molding because the plastic powder is rotated during the heating process. This rotational move happens at two axis. The first is the horizontal axis, there the whole arm of the machine is rotated. The second axis is the vertical axis. There the plate, which is mounted on the arm and has the tools on it, is rotating itself. Through this rotational move the plastic powder is spread evenly on the insides of the tool and the wall thickness is the same at every point. Thereby material stretching at edges is prevented. In the following the production of a seamless hollow plastic part made of one part without stretched edges in the roto mold process is explained. Through that process the plastic part is really robust and form stable. The whole roto mold process is without any pressure except the gravitation which results in strainless hollow parts. The pressureless roto mold process is divided into four production steps:

Filling phase

At the beginning the steel or aluminum tool is mounted on one arm of the machine. Contrary to other processes in the rotational molding process more than one tool can be mounted on one machine arm as a plate is on the machine arm which holds the tools. Now the rotation tool is open and can be filled with plastic powder according to your wishes and requirements concerning the plastic formed part. Through the amount of powder we are able to regulate the wall thicknesses of the parts individually. During the filling phase also attached parts may be added such as threads and metal inserts. Those will be completely inseparable enclosed during the rotational molding process. The tool mostly consist of two parts, but depending on the complexity it can consist of more than two parts. Those parts are closed with bars and bolts after the filling phase.

Heating process

In the next step the arm of the machine with the filled tools goes automatically into the heating chamber of our roto mold machine. During the heating phase the plastic material is evenly heated at temperatures between 200 °C and 350 °C. During the complete heating phase the machine arm is rotated over two axis that are standing vertically towards each other. During this rotation the whole machine arm is rotated while the plate, which is mounted on the end of the machine arm, is rotating itself as well. Because of this rotation the process is called rotational moulding. During this bi axial rotation the plastic powder is moving over the insides of the tool because of the gravitation. When the melting point is reached the powder is clinging to the insides. Throughout the continuous bi axial rotation layer after layer is built on the insides of the tool until all of the material is melted. Through the pressureless production process the plastic is spread evenly on the tool walls and hollow parts are created without material stretching.

Cooling phase

After the heating phase when the material is completely melted, the arm of the machine goes automatically from the heating chamber to the cooling chamber. Throughout the arm stays in the bi axial rotation movement. In the cooling chamber the melted plastic is cooled down to its extraction temperature of approximately 90 °C. In order for the insides of the form to be even, the arm stays in the bi axial rotation movement throughout this phase. Depending on the material there is a shrinkage of the hollow plastic part during the cooling phase. We only cool our plastic parts with air to ensure an even and slow cooling in order to prevent deformation of the plastic part. With the help of cooling applications, the formed part is fixated in its warm state. Through that we are able to control the shrinkage and maintain even tight form part tolerances.

Withdrawal phase

As soon as the required withdrawal temperature is reached in the cooling chamber, the rotational machine goes automatically to the withdrawal station. There the form can be opened and the formed part can be taken out. If the form more complex so that there are more than two parts needed, first all parts have to be opened in order for the formed part to be completely taken out. Forms with more than two parts makes it possible for us to realize even complex forms. Through our rotational molding process we receive technical plastic formed parts in high quality, stress less and seamless in every required size. After the formed part is taken out the machine arm automatically goes to the filling station where it can be filled again and where the whole process starts anew.

Advantages of the rotational molding process

The thermoplastic rotational molding process offers many advantages over other processes.

Large dimensional hollow parts

With our production process we are able to produce robust and seamless plastic parts as well in closed form in dimensions from 0,1 up to 40.000 liter as small series as well as large scale production.

Openings

We can also produce any openings in the plastic part on demand as well with plastic or metal female and male threads.

Complex geometries

Geometrically specialties such as complex forming with re-entrant angles, ribbings, recesses, recessed grips or as well continuous connections can be done during the production process. We also offer the possibility of modular forms to realize a form for more than one formed part.

Metal inserts

Metal inserts, we apply in the production process, will be put permanently into the melted plastic and thus have a strong connection with the formed part. This increases the quality of the product and reduces the assembly times as super structural parts can be screwed on directly without complex adjusting.

Materials & additions

We use many materials such as polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), polycarbonates (PC), polyamide 6 (PA6) and polyamide 12 (PA12). Furthermore we have the possibility to add additions such as pigments and additives in order to adapt the material characteristics and the visual appearance to your wishes.

Colors & pigments

On demand we can produce our standard product range as well as your specified formed part in all RAL and special colors. Depending on your request we can also add color additives such as persistent or metal effect pigments. Thus you can design the visual appearance of your product individually.

Wall thicknesses

Through our pressure less production process we can also realize in radius areas an even wall thickness without material stretching and stresses. Additionally we can realize different wall thicknesses in only one form through our high quality forms.

Implementations

Implementations can be added directly into the formed part. Thereby so called kiss of connections are inserted into the form with creates a canal from one form wall to the other. This can for example be used in order to install a formed part on the wall.

Possibilities in the rotational molding process

In the rotational process there are many different possibilities to design a plastic part and to combine different characteristics to adapt it to your application. Our experienced team consults you if you have questions and supports you through the whole production process of your plastic formed part.

Completions

Through different possibilities of the completions different characteristics can be shown in your plastic part. For example containers can have isolating characteristics as well as different colors on the outside and inside.

One-wall parts

Our one wall produced plastic parts are often used for tanks, containers, cover panels and caps and are very robust and stable.

Two-wall parts

With a special composition in the form we can produce two wall parts which have an increased stability and lifting force.

Two-time multilayer

The two times multilayer offers the possibility to combine different materials and their characteristics such as color and stability. With that you may have for example a blue outside and a white inside.

Three-time multilayer

It is also possible to create three-times multilayer. Thus for example a middle layer of foam can be produced which is very stable and has no direct contact to the medium due to the third layer.

Foamed parts

We foam two-times multilayer parts during the production process with expanded PE material or after the production process with PUR foam. Thus the stability of your formed part is greatly increased. Additionally special isolating characteristics can be optimized which is for example used for cooling boxes.

Ripping

Geometrical specialties such as complex ripping can the produced during the production process in every form and wall thickness. Because of our pressureless production process even in radius areas no material stretching and thin wall thicknesses will happen.

Integrated lid

Through our production process we can produce plastic formed parts with an integrated lid. The plastic part is produced with a lid as one part. After the production process the in between part the so called lost head is removed and the lid can be put onto the bottom part.

Handles

As well recessed grips can be realized directly in the plastic formed part. Therefore extricable parts are inserted into the form which are re melted by the plastic and build the handles in the plastic part. Those handles are used for example for transportation boxes, electro distributor and cooling boxes.

Inserts & mountings

With the help of inserts and mountings you are able to add your plastic part directly to your application. Because those inserts are molded into the plastic part directly in the production process no after processing has to be done and your tank is ready for connection.

Metal thread inserts

We can add metal thread insert directly into the formed part for example to connect the tank with tubes.

Plastic female threads

Directly produced plastic female threads can be realized by extricable brass inserts in the form. The thread is suitable for the direct connecting of fitting pins.

Plastic male thread

Plastic male threads can be also directly realized in the production process as well through extricable brass inserts. This thread is especially suitable for the connection of lids.

Plastic stamping

Through the use of aluminum or steel cones, which are added to the form and are melted in during the process. Before the plastic formed part is extracted the cones are removed. In those emerging cones self-cutting screws can be assembled in order to fixate for example armatures.

Sealing surfaces

Sealing of screws through flat or o ring sealing can be directly realized in our production process. The flat area is built in the form thereby shows precisely in the plastic formed part. Thus the supplementary milling of sealing surfaces is already done during the production process.

Crane eyes

The transportation of plastic parts especially after a certain size and weight may be difficult. Therefore you can add crane eyes to your plastic part in order to make the transportation much easier and transportable.

Cable fixations

Cable fixations such as cable canals or tube fixations can also be directly realized in the production process. Thereby tubes and cables can be lead protected at the formed part.

Form possibilities in the rotational molding process

For the rotational molding process there are basically two different kinds of forms. Those forms are made of different warmth conductible material, depending on the requested product. Every form has different advantages and disadvantages that have to be taken into consideration. The decision on which material is the right one for your product depends on different technical criteria. In the roto mold process such criteria are for example the size, complexity, precision, surface structure and the planned number of products. Further decision making factors are the costs and the time of production. In the thermoplastic rotational molding process mostly forms made of steel panel or casting molds made of aluminum are used. The decision which material should be used depends on such factors as mentioned above. Aluminum forms are most of the time milled out of one part or poured depending on the size and complexity. It is mostly poured when plastic parts with a great size are asked for. Afterwards the forms are heat treated to reduce stress. If the form is milled there may be high tolerances and it has to be milled from both sides so that the heat can get into the form during the production process. The poured ones have the advantage concerning surface structures. Different surface structures can be integrated into the process in order for your product to have the demanded surface and visual appearance. For great scale plastic parts or parts with a low difficulty and complexity mostly forms made of steel panel are used. Thereby the panels are put together or welded together, which is why a low complexity is more suitable than a rather high one. The wall thickness can vary between 1,5 and 4 mm. Through our pressureless production process we are also able to realize even in radius areas an even wall thickness without stretches. Furthermore we have the possibility to realize different wall thicknesses in one form. This gives you the possibility to realize different wall thicknesses even after the form is produced.