The LTT and LTF model pie-making systems represent high-performance, customizable machines for industrial-scale production of tartelettes or pies. The LTT system deposits and blocks pies in indented baking trays for transfer to GEA tunnel ovens, while the LTF system forms pies in individual moulds.
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Our compact Tartomatic pie-making machine is ideal for producing different shapes and sizes of pies, quiches and tarts, and can be configured with a volumetric extruder to make biscuit crumb cheesecake bases, and integrated with a volumetric depositor for cream or jam.
The Minitart system is a compact system for pies and tarts, which can process at a higher capacity than the Tartomatic. Like the Tartomatic, the Minitart technology can be fitted with a depositor for cream and jam, and with a moulding unit for lids and lattices.
The industry-leading Tartomatic machine is easily customizable for producing a wide variety of sizes and shapes of products, from traditional round-, square- and triangular-shaped pies and quiches, to specially shaped tarts, including hearts and stars. The basic Tartomatic unit comprises a dough-billeting roller extruder, and a turntable on which the foils are placed and product molding is carried out. The extruder guarantees the highest accuracy volume of dough, as well as gentle and efficient handling. The dough portions are then molded using a heated blocking die, which provides high precision stamping to produce the perfect pie shell with exactly the right dimensions and thickness, every time.
Adding a volumetric extruder for biscuit crumbs allows the Tartomatic system to be used for making cheesecake bases. A volumetric piston depositor for cream or jam can also be integrated in line, and a rotary molder unit can be provided to add personalized lattice tops or lids.
Talk to GEA to find out more about options that are available for the versatile Tartomatic machine.
The Minitart machine has been developed to offer increased production capacity, combined with flexibility for processing pies and tarts.
The unit comprises a belt conveyor on which is fitted the volumetric extruder and blocking system. The conveyor is driven by a servo-motor, which guarantees highly accurate positioning of the specially designed trays under the extruder and blocker. Once the tray is in place, the volumetric extruder cuts and deposits the dough billets into the tray indents. The mechanical blocker with individual pneumatic compensation then blocks the dough billets into the tray indents to produce the highest quality pie, every time.
Downstream of the dough blocking, the Minitart platform can also be fitted with a depositor for creams and jams, as well as a customizable molder for lattice tops or lids.
The high performance LTT and LTF lines for pies and quiches are customizable and can be configured to the exact requirements of a wide range of products and production capacities.
The LTT line forms pies in indented trays. The system comprises a brushless chain conveyor that ensures perfect positioning of the trays underneath the working units, on which the dough billeting extruder and the blocking press are fitted. The unit’s volumetric extruder first portions the dough billets and accurately deposits them within the indents of the tray. The blocker then carries out the more delicate job of blocking the pie or quiche, using a pneumatic compensation system that ensures the perfect shape for every indent, every time.
In contrast with the LTT line, the LTF unit forms pies in individual foils. A denester carries out the first step of placing the foils, one or two rows at a time, into holes in the interchangeable, perforated platens. The advantage of forming products in foils is that after blocking and decoration, the pies can be transferred directly to the freezing or packaging section without the need for depanning. Both the LTT and LTF pie production lines can be equipped with volumetric filling depositors and a rotary molder for forming lattice tops or lids.
You may have heard about the traditional process of sand casting, where molten material gets poured into a mold and solidifies into a shape. However, that final product often doesn’t meet precise requirements right away – a series of machining operations are carried out to achieve the right dimensions and surface finish.
Shell molding is a refined casting approach that tackles these challenges. Instead of relying on loose sand, it creates a thin and hard shell of sand and a thermosetting resin binder. This shell provides superior dimensional accuracy and a smooth surface finish, reducing the need for additional machining.
This article explores the process of shell molding, the materials best suited for it, and its multiple product applications across industries.
Shell molding is also known Croning process, after its inventor, Johannes Croning – a German engineer who devoted his life to developing casting techniques and machines. The discovery of shell mold casting was one of his major innovations that paved the way for more accurate building of parts.
Shell casting is an expendable mold casting technique in which a thin-walled shell of sand and thermosetting resin binder is used as a mold. This shell, unlike traditional sand molds, is strong and resin-bonded. It results in superior dimensional accuracy and a smooth surface finish.
The shell mold casting process is slightly lengthier than the sand casting process as it involves a series of preparatory steps. Here’s how the process works:
For casting you need a metal pattern that accounts for shrinkage and machining allowance. Usually, manufacturers make it via machining, and in two halves. Iron and steel are common. However, graphite is also an option for reactive metals.
This is the most critical process in the journey that starts with metal pattern heating at 230–340ºC (450–650ºF). Then, technicians lubricate it with calcium stearate so the sand shell doesn’t stick to it.
The whole pattern gets hung over a dump box containing a blend of fine silica sand and thermosetting phenolic resin. That box is flipped to cover the hot pattern with the sand-resin mixture. The heat from the pattern slightly cures a layer of the mixture, forming a firm shell around 9–20 mm thick.
After a few seconds, they invert the pattern and box again to let any loose, uncured sand fall away. This leaves just the cured shell adhered to the pattern. Finally, the shell gets placed in an oven for complete curing. This is where it gets in its tensile strength (350 to 450 psi). We require a two-part shell, so the same mold construction process gets repeated for the other half.
After the construction of both shelves, their assembly starts. Clamping or gluing are two options for joining.
For added support of the shell, technicians may place it inside a pouring jacket or surrounded by sand, gravel, or metal shot. Then, they pour the molten metal into the mold cavity. This may done by hand or by machine.
The metal cools naturally. Once it’s solidified, the workers may open or break the mold to remove the cast part. Then, the casting is cleaned or machined as per finish requirements.
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You can use shell casting for most types of metals, pure and alloys – both ferrous and non-ferrous.
Cast iron was once the most cast metal due to its mechanical properties. Still, its use is prevalent in the industry. Fray cast iron, nodular iron, white cast iron, malleable iron, and alloy cast irons are popular for this casting.
Steel castings are known for their high tensile strength and toughness. The best steel options are:
Aluminum alloys are suitable for lightweight applications for instance aerospace. ASTM A356 and ASTM 360 are common aluminum alloys for mold casting.
Copper is a ductile material with excellent conductivity and corrosion resistance. So, the use case is applications requiring these properties, for instance, electrical components. However, copper alloys are expensive and offer less strength than steel.
Shell mold casting is popular for its better tolerances, surface finishes, and versatile material capabilities.
Here’s a list of advantages, the casting process has to offer:
Some downsides of shell casting include:
Shell casting is very effective in replicating metal parts with dimensional accuracy in a short time. So, the shell-molded products span across multiple industries, including automotive, aerospace, energy, medical, etc.
The presence of resins increases the surface smoothness, which eliminates the need for extensive post-processing. Subsequently, it requires less labor & time, reducing the overall production cost. For these reasons, manufacturers prefer the shell molding method for the production of small to medium-sized metal parts
The table below outlines the specific shell molding applications in various industrial sectors;
Molding is a broader technology that refers to shaping the material by melting and solidifying it in a die or mold, shell casting is one of them. Besides this, there are other closely related techniques, such as sanding casting, die casting, and investment casting.
Sand casting and shell molding are sand mold casting techniques. However, the mold creation process is different. In sand casting, the whole packed sand itself acts as a mold. Whereas, shell molding uses a thin shell of sand and resin binder as the mold.
Sand molds are loose and the likelihood of surface defects and dimensional inaccuracies is higher. In contrast, expendable molds are thin and hard, and shell-molded products have a better finish.
Investment casting utilizes a different casting approach than shell molding. It uses a wax pattern for each casting. These wax patterns are assembled into a tree structure (wax sprue), coated with a ceramic slurry, and then melted away to leave a mold cavity.
So, both the pattern and mold materials are different. Shell molds are usually metallic. Whereas, in investment casting, they have wax build. Shell casting uses sand mold whereas investment casting utilizes refractive ceramic.
Although the shell molding surface involves a better surface finish, the finish of casted products is much higher in the case of investment casting, up to 1.3 microns.
Shell and die casting are both metal casting techniques, but the major difference is the mold. Die casting uses a permanent metal mold, or die, and applies high pressure to inject molten metal into the mold cavity. Whereas, shell casting uses an expendable shell mold of sand + resin.
Unlike die casting, shell molding doesn’t require high pressure; instead, it relies on the strength of the resin-bonded shell to achieve precision. Also, die casting only works for metals with low melting points and parts with simple geometries.
Injection molding is another precise mold technique; however, it primarily focuses on replicating plastic products. In this process, molten plastic gets injected into a metal mold under high pressure, where it cools and solidifies into the final shape.
So, the major difference between shell and injection molding is their target materials and casting approach. The shell molding process involves pouring molten metal into a sand (expendable) mold. Whereas, injection molding revolves around the injection of plastics into a solid (non-expendable) mold.
Are you working on a part or prototype that requires metal casting or plastic molding? Let RapidDirect handle it. We offer a complete range of metal casting and plastic injection molding services to meet diverse project requirements.
For metal casting, consider our precise die casting services, which are ISO : certified. For plastics, we offer both injection molding and insert molding options. Our products get quality checks with rigorous inspections at every stage – from pre-production to final output.
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