10. Molding and casting¶
This week I worked on defining my final project idea and started to getting used to the documentation process.
Research¶
MOLDING AND CASTING¶
MOLDING¶
Injection molding is a forming process using molds. Materials such as synthetic resins (plastics) are heated and melted, then sent to the mold, where they cool to form the designed shape. Disposable and removable molds: They are usually made by models that can be made of wood, plastic, wax, plaster, sand, polyurethane or metal. When these are destroyed when making the piece, they are known as disposable, and when they serve multiple functions, they are known as removable.
HOW TO MAKE CAST MOLDS¶
• For the manufacture of molds, the following steps are followed: • The part is designed. • The mold is made with its shape and what material will be used. • The material is poured in liquid form, so that it later hardens. • The part is removed. • It is cleaned. • It is polished if necessary.
WHAT ARE THE TYPES OF MOLDING?¶
The term molding, derived from mold, can refer to: The action and effect of molding. The process of modifying solid materials through molds to obtain parts with a certain shape. … Injection molding. Blow molding. Lost wax casting. Vacuum molding. Rotational molding and/or Rotational molding
FOUNDRY¶
The process of producing useful parts or objects from molten metal is known as the casting process. This process has been practiced since 2000 BC. It consists of pouring molten metal into a container in the shape of the part or object to be manufactured and waiting for it to harden as it cools.
WHAT PARTS ARE MADE BY CASTING?¶
There is a wide variety of parts manufactured by casting, for example, gaskets, nuts, pipes, valves, accessories… These parts are used in many sectors such as automotive, aerospace, railway, construction, agriculture, mining, machinery, defense, industrial plants, electrical, household appliances.
WHAT TYPE OF FOUNDRY IS THE MOST USED?¶
The most commonly used martensitic castings are white. However, martensitic castings were also manufactured, which are of more restricted uses. These castings usually contain 4.5% nickel, 2% chromium, and low silicon, 0.50%, reaching variable hardnesses from 500 to 700 Brinell. The master cast is used to make a wax mold from rubber, which is heated and vulcanized around the master cast to make a flexible wax mold. Wax Pattern Production: Molten wax is injected or sometimes poured into the rubber mold
RESIN¶
The resin, in its raw state, is a liquid with a viscous consistency that can be translucent or transparent. By adding two components (catalyst and accelerator) a chemical reaction called polymerization occurs that causes the resin to gel or harden. The transparent liquid resin is the flagship product of Diseños Epóxicos; Due to its technical characteristics, it is used for epoxy resin work on wood, floors, countertops, crafts; and a wide variety of artistic and industrial applications.
CATALYST¶
The catalytic converter’s mission is to reduce the polluting elements contained in the exhaust gases of a vehicle through the catalysis technique. It is a device installed in the exhaust pipe, near the engine, since the gases there maintain a high temperature. A catalyst is a substance that, without being modified or consumed during the process, changes the rate of a chemical reaction. Catalysts can be positive, when they speed up the reaction rate, or negative, when they slow down the reaction rate.
DESIGN IN 3D Auto CAD¶
In the work for the molding and casting, we first design in the Auto CAD a mechanical element that is the gear with a diameter of 50mm with a thickness of 20mm with 18 teeth, after designing in XY coordinates it is changed to a 3D template where the extrusion of the object is made. then send in DXF format.
MILLING WORK WITH MACHINING WAX¶
The machining will be placed on the work table of the milling machine, the edges are fixed with silicone so that the material does not move after it, we enter the exported Auto CAD file, then it is uploaded to modsproject.org, where they are made some adjustments and then it is sent to the VPanel model software for Roland SRM-20, where the parameters are calibrated to carry out the molding of the designed object, the duration of the molding is approximately 6 hours, after the molding is finished we proceed to prepare the inputs, the resin and the catalyst in exact measurements, having the mixture well made, proceed to strain and let it rest for at least 1 day in order for the model to be very dry and resistant, chemical and physical changes of the materials and materials are observed. supplies throughout the process.
RESIN AND CARALIZER¶
They are two chemical elements to make molds, both are mixed in equal quantities, then it is poured into the mold after a day of drying, the model is removed from the mold, the object made, in this work a 3D gear was designed in Auto CAD then it is exported in DXF format, after which it is uploaded to modsproject.org where some adjustments are made and then sent to the VPanel for SRM-20 Roland model software where the parameters are calibrated to perform the molding of the designed object over time The duration of the molding is approximately 6 hours, after the molding ends, we proceed to prepare the inputs, the resin and the catalyst in exact measurements, having the mixture well done, we proceed to cast and leave at rest for at least 1 day so that the This model is very dry and resistant, throughout the process chemical and physical changes of the materials and inputs are observed.
FINISHED MILLING WORK.¶
The milling in the mechanized wax is observed. The object designed with a good finish lasted approximately 5 hours of molding. Now we remove the wax from the platform, we clean the remains of chips and the product is observed. Now it’s time to prepare the resin with the catalyst, having a total measure of 6 grams, you want to say 3 grams of resin and 3 grams of catalyst and we proceed to mix the chemical, already mixed, we put the machine to remove the bubbles, then spray with the liquid that It will allow us to easily extract the object, we pour the mixture into the object and put it to rest for a day at the end we have the product.
RESIN AND CATALYST FINAL PRODUCT OF THE MOLDING¶
The mixture of the two chemical elements after 24 hours forms a mold of the elaborated design where we can have more element and be able to reconstruct mechanical elements, with the excess of the combination of the chemicals we make another mold for the design, it cannot be easily achieved. Thus, with this molding process we can make replicas of objects and mechanical elements without difficulty.
