New Part: Cigarette Case

posted in: Machining Projects | 0

I’m going to start some works in order to realize some tests. Specifically I’m going to realize the model which there will be created the glass fiber molds of a Cigarette Case, to do it later in carbon fiber. As you can see it’s a very exclusive article, although it’s for smokers, it’s always a nice object.
First step, as always, is the modeling. I’ve started with a geometry defined with aesthetic criteria, and next I will prepare the machining phase. The cigarette case is symmetric, that means, both parts are the same, it will be opened by the bigger side, and they are symmetric by this plane. It’s also symmetric respect the other two orthogonal planes, what make the design much more easy. So I only need to draw one quarter

pitillera

Esta seria la pitillera terminada. Un diseño sencillo

I’ve left two planes in one border, to screw the hinges, I must to take into account to planify the fabrication.

I must to design also the real size model, for which I must to define some surfaces to make the apply of glass fiber more easy. Thanks to the simmetry, I only need to machining one part. This would be the looks:

master
This is what I must to machining, from here it will be easy to get the glass fiber part, So let’s go to CATIA to prepare the program:
pitillera 01

The process is very simply, basically the machining strategy will be very similar to the last post. First a roughing, and after a finish machining with a spheric tool. But there are some details:

First, the roughing is done automatically, but I must to define the security planes, the roughing stock volume (with the real dimsensions), the tools I’m going to use, and the feed rate and machining deep.

pitillera 03

After this, I need to define some parts, because I’m going to realize some paths with a finish tool 2 lips 90º to define:

  • By one side, the surface where the inclined surface ends.
pitillera 02
  • By other side I will define the line who separate the part from the other helping surfaces
pitillera 04
Now it’s time of the finish phase, changing to the spheric tool, and doing the paths. This paths are divided according to the direction of the zigzag, I’ll explain: The top part, i don’t really matter the zigzag direction, but in the incline surface, I don’t want to keep the same direction, because I would lost definition, so I will program the paths like this:
pitillera 05
With this first finishing operation, I have two incline surfaces and the top surface. The other incline surfaces, must have the same orientation, so I’ll adjust the operation as the others, but only in the surfaces I left for machining:
pitillera 06
Logically, I lack the corners, but if I only can choose ortogonal directions, I will lost part of the precision in this corners, so I will create a 45º orientation only for corners. This is the result:
pitillera 07
In this easy way, the part is already defined, and with a very similar surface quality in all sides, as you can see in the simulation:
pitillera 08
If you look more carefully, you will look that thanks to this orientation, the finish quality of the surface is the same in all the part, what make easy the  posterior works (sanding)
pitillera 09
Now I will show the real machining process:
IMG_20121021_131029
Origin setup and LINUXCNC configuration
IMG_20121021_131035

Placement of the stock in the table. Here I’ve installed temporary the aspirator, very usefull, to avoid the dust around all the room.

IMG_20121021_131103

Ten first paths of the roughinh

IMG_20121021_133229

Once the roughing is finished, contour path and define the surfaces as I told before.

IMG_20121021_133233

Detail of this paths

IMG_20121021_133916

And the finish starts. This time with only one operation I will reach the real surface, so i will save time. In total, it takes 58 minutes working, without the tool changing time. So it’s important to optimize the programming.
Conclusion, the machine works fine! a proffesional work!