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CNC MANUFACTURING LIMITATIONS
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INTRODUCTION
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This topic will help you better understand some of the restrictions associated with the CNC Manufacturing of F1 in Schools Car bodies using a 3 - axis CNC machine.
First - check out our short video that provides a time lapse view of a typical F1 in Schools CNC machining process:
It is important that car designers have an understanding of the limitations, particularly if you are designing a car for the Test Driver Challenge or Rookie Category of the UAE National Competition.
Test Driver Challenge and Rookie Category Cars are only allowed to be manufactured using a left side and a right side of car machining process. In essence, this means that when you view your car body in the side view, you must be able must be able to see all surfaces to be machined.
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F1 IN SCHOOLS CAR BODY MACHINING METHOD - ROOKIE CATEGORY
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F1 in Schools Car Body Machining Method
The recommended standard CNC machining method, and method used for Test Driver and Rookie Cars, is to machine car bodies using two machining operations, one operation from the left side of the car and one from the right side. For each operation the F1 Model Block is mounted on its side in the CNC machine via clamping in the special F1 in Schools Machining Fixture. This method provides for a wide range of car profile designs to be machined with a minimum amount of machining operations. The picture below illustrates the CNC machine setup for side machining operations:
The green arrows above indicate the 3 axis direction system of the CNC machine. These are the three axes of direction that the cutting tool can move in, often simultaneously, in order to remove the excess Model Block material revealing the profile of your F1 in Schools racer. The standard method of manufacture is to machine the car body using two machining operations, one machining operation on each side of the car. The right side of the car is machined with the Model Block mounted as pictured above, the Model Block is then rotated 180 degrees about the x axis to machine the left side of the car body. The left side machining operation is simply a mirror image of the right side.
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DIVE DEEPER
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The video below provides even greater detailed explanation and compares 3 axis CNC machinining, (the standard for F1 in Schools), with multi-axis CNC machining methods and technology.
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THE BASICS OF CNC MACHINING
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In industry, all products are designed with consideration given to any limitations that may exist due to the available or chosen manufacturing methods. An F1 in Schools car is no different. It is important to understand the manufacturing technology and process so that the car designer can create a car body shape that is actually possible to manufacture by a CNC machining process.
CNC (Computer Numeric Control) machining is a very important and widely used manufacturing method in industry. Many schools are equipped with 3 axis CNC machines which is the minimum requirement for car body manufacture in F1 in Schools. Schools without access to this technology can have their car body designs CNC machined by the experts at Yas in Schools.
The following video provides a good overview of different CNC machining methods used in industry
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F1 IN SCHOOLS CAR BODY MACHINING METHOD - PROFFESIONAL CATEGORY
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For professional category teams, machining can be done on the top and bottom of the car by rotating and mounting the model block with the top or bottom facing upward in the fixture.
Due to there being only 3 axes or directions of movement that the cutting tool can move in, some shapes or profiles may not be possible to machine. The diagrams below help explain this further
Professional Category teams can have additional top and bottom machining operations. If the above right illustration was for a Professional Category team, the block could be rotated 90 degrees anti-clockwise and then the top surfaces of the wing feature shown in red could be machined successfully. However, it would still be impossible to remove the material shown in red under the wing features.
Finally, the size and shape of the cutting tool needs to be considered. The standard machining process for F1 in Schools car bodies uses a ¼ inch (6.35mm) diameter ball nose shaped cutter. Due to the 6.35mm Ball Bose end, all internal corners on a car body design will always feature a 3.175mm radius fillet. These fillet radii can be seen in the diagrams above and below.
Hopefully now you have a better understanding of the CNC machining process used to manufacture F1 in Schools car bodies and the few limitations that this imposes. You should now keep these factors in mind as you unleash your creativity in designing your F1 in Schools car body.