Reportage casting : the inverted casting

Design and implementation of an innovative method of casting foundry, This is the challenge that took a team of engineering students of Arts and crafts in Lille.

A tradition of Galas Arts and trades is to distribute objects made by the students themselves in the workshops of the school. These objects are always ashtrays, and if the interest of one such utensil is also stronger could be, This tradition is maintained and even the magnitude !

A team of students organizes itself to develop a supportive project technicality and reduced budget, and with the available resources : traditionally machining, smelter or forge. These methods are the pillars of Arts and crafts workshops, but no doubt will we someday made ashtrays 3D printing !

This approach, always supported by professors of manufacturing, allows to combine projects “extra-scolaire” the teachings of the school, while promoting the spirit of initiative and the cohesion of the students. What more ?

The draft of the Grand Gala of Lille 2013

The theme of the gala being mythology, the ashtrays team decided to an amphora hollow. Easy to say and draw in CAD, But how to perform effectively ?

Thanks to the ingenuity of the team and Professor of foundry in Lille, Philippe Costes, an absolutely innovative solution Foundry for aluminium was imagined : the inverted casting. With this method, need more core to scoop the amphora, the mould is mounted on a pivot that allows the switch to evacuate, a few seconds after casting, the center of the room molten metal, who has not had the time to solidify. A higher pin allows for more precise moulding of the mouth of the amphora, and the uprooting of the core hollow casting.

The tension was palpable during the preparation, but the result obtained from the first casting showed the relevance of the choice of the team when designing : the result is spectacular ! More than 1100 good parts have been produced in just five days, with a time of medium cycle about 1 min 10s !

Below you will find a selection of photographs taken during my reporting on the grounds of the school.

Reportage casting : the inverted casting

report Foundry : the inverted casting

Overview foundry Arts and Crafts Lille, which are made every year ashtrays for the Gala des Arts et Métiers : the Fignoss.

Foundry arts and crafts - Empreinte du cendrier dans le moule dit en "coquille", in which will be poured molten aluminum

Footprint in the ashtray said mold “shell”, in which to cast molten aluminum

report Foundry : the inverted casting

The mold is in two movable parts, plus one “brooch” on the top of the jar, for improving the surface finish of the mouth thereof.

Foundry arts and crafts - Fitting the mold, with its rare specificity in the world of foundry : the ashtray is molded with the technique of reverse. Cette technique permet d'avoir une pièce creuse sans "noyau" in the mold. To achieve the molding, to pour aluminium up to brim into the mould, then return after a few seconds the mold. Aluminium in contact with the mold will be solidified, While the inner, always liquid, out of the mold : we obtain a hollow part !

Fitting the mold, with its rare specificity in the world of foundry : the ashtray is molded with the technique of reverse. This technique allows a hollow without “core” in the mold. To achieve the molding, must pay the aluminum to the brim in the mold, then return after a few seconds the mold. The aluminum in contact with the mold is solidified, while the interior, always liquid, out of the mold : we obtain a hollow part !

report Foundry : the inverted casting

The assembly is disassembled and checked before the first test.

report Foundry : the inverted casting - Point central de ce montage de coulage "renversé" : the pivot of the mold.

Central to this casting mounting “overturned” : the pivot of the mold.

report Foundry : the inverted casting - The aluminium bars are placed near the oven where they will be melted.

The aluminum bars are placed near the oven where they will melt.

Foundry arts and crafts - The mold is heated the gas to 220 ° C for the purposes of the release.

To mold parts, the shell is heated and coated with a special mixture, le poteyage. This will prevent the aluminum to adhere to the mold, and define the surface of the part. The mold is heated with gas up to 220 ° C for the application of release agent.

report Foundry : the inverted casting - A thermocouple is used to check the temperature of the mold. Ici 212°C : It's still not.

A thermocouple is used to check the temperature of the mold. Ici 212°C : it is not always that.

report Foundry : the inverted casting - The different parts of the mold must be handled with great care.  Numerous hours of work would be lost if a shock were to deform the gasket.

The different parts of the mold must be handled with great care. Numerous hours of work would be lost if a shock were to deform the gasket.

report Foundry : the inverted casting - The used coating is here of graphite containing particles with a size of six microns. It is sprayed onto the mold with a special gun.

The release agent used here is graphite containing particles of a size of six microns. It is sprayed onto the mold with a special gun.

report Foundry : the inverted casting - Projection of graphite release agent on the mold

Projection of graphite release agent on the mold

report Foundry : the inverted casting - Cendars-AM-Lille-photo-Guilhem-de-Lepinay-21

report Foundry : the inverted casting - The same, the ladles used to transport aluminum from the crucible to the mold must be heated and poteyees.

The same, ladles used to transport aluminum crucible mold must be heated and poteyées.

report Foundry : the inverted casting - Cendars-AM-Lille-photo-Guilhem-de-Lepinay-26

report Foundry : the inverted casting - Brooch, room on the upper part of the amphora, also receives the release agent.

Brooch, from the upper part of the jar, also receives the release agent.

 

report Foundry : the inverted casting - Aluminum is now melting in the oven. More than 700 ° C, must be very careful when handling the molten metal.

Aluminum is now melting in the oven. More than 700 ° C, must be very careful when handling the molten metal.

report Foundry : the inverted casting - Dressing performers : Leather rigueur !

Dressing performers : Leather rigueur ! Apron and gaiters add to the blue full work.

report Foundry : the inverted casting - The color should bring molten aluminum, the flow, then recover the surplus to put it back in the oven.

The color should provide molten aluminum, the flow, then recover the surplus to put it back in the oven.

report Foundry : the inverted casting - Aluminum is poured from the ladle into the hole of the mould, looked at 30 ° C for better metal flow.

The aluminum is poured from the ladle into the hole of the mold, bent at 30 ° to improve the flow of metal.

report Foundry : the inverted casting - First amphora output : almost perfect ! The joy of the students is palpable : All their efforts were rewarded with the first successful casting.

First amphora output : almost perfect ! The joy of the students is palpable : All their efforts were rewarded with the first successful casting.

report Foundry : the inverted casting - The following streams are sometimes little trouble.... It is the job that fits !

Many jars out of the mold without defects, but there are still some small problems… It is the job that fits !

report Foundry : the inverted casting - Months of hard work rewarded with a few successful examples of ashtrays.

Months of hard work rewarded with a few successful examples of ashtrays.

 

A success for the Foundry of l’School of Arts and crafts of Lille

Lille Foundry has not said its last word, and if most French foundries were today relocated, This story proves that knowledge make this craft is not yet forgotten !

 

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