Sand casting using a pattern
Slide 32
The first step in casting with a pattern is to create this digital model. We will of course use the initial digital model from which the following machined surfaces will be removed, such as:
The notches,
The holes and countersinkings,
The central bore.
Slide 33
The pattern will be machined this time using the 3D (3-dimension) CAM. In the same way as for the 2D1/2 CAM, it is first necessary to assemble the reference model using the rough part and then we create the machining functions. We will only see simulation images and we will not go into the details of the 3D CAM. Here we can see the beginning of the rough-machining[1] step.
Slide 34
In this picture we can see the part at the end of the rough-machining step. The solid cylindrical[2] cutter machines in a series of passes at different heights. Around the part we can see a series of small steps.
The finishing step is carried out using a spherical cutter[3] called the cherry. The passes are now carried out in any plane which explains why we say 3D CAM or surface dressing.
The surface state of the finished part depends on the distance set between each of the passes.
Slide 35
The top of the part is now finished, and finishing operations for the sides are about to begin.
The visual state of the surface, as it appears in the simulation, is very close to the real result obtained with machining; that is to say the groove marks that we see would be present if we stopped the real machining at this precise moment.
Slide 37
The simulation of the part is now finished and all the surfaces have been finished. The result of the real machining can be seen in this photo. We can now move on to casting.
Slide 38
This photo shows the half box in which we can see the sand moulding made with the pattern of the part machined beforehand. The second half of the box is used to close the box.
This is a photo of the half box after casting.
In the last photo, we can see the cast part, the flow pipes and the feeder head used for filling
