EDM Project Web Page

Design Communications 2

Team: Sean Hesse

Original Device Design: Robert Hesse

 

 

The First Concept

         

 

The first concept that I experimented with was basically just an adventure in modeling.  I “kicked around” a few ideas for the design and modified them until I came up with a final assembly of my first concept proposal.  This concept involved a custom fitting to mount the stand pipe to and a mounting arrangement that would require the drainage hose to be run down the center slot of the milling machine.  After further investigation and discussion, I found this idea to be unacceptable by both the manufacturer’s and designer’s standards for the design.  This inspired me to modify the design and come up with a second concept design.

 

                    

(The assembly looked roughly like this but with angle iron on the sides for the T-Bolts to clamp to. The base is supposed to be a rendering of the table on a standard Bridgeport universal milling machine. The appearance of the assembly changed because some parts of the assembly were modified causing the assembly to update.)

 

I started the second concept out by making a CONCEPT SKETCH. After I drew up the concept sketch and showed it to Robert, I began to model the device in Inventor. Once the model was finished, I made the part drawings (Angle iron, angle iron w/hole, drainage coupling, work tank, assembly one, assembly two, and the welding assembly). The following models were made for this project: Angle iron w/ hole, angle iron, drainage coupling, work tank, T-bolt, assembly 1, and assembly 2.  I also created a design guide for the project.

 

 

 

This is what the assembly of the work tank ended up looking like (mounted to milling table).

My supplemental design utilizes a coupling that drains out of the side of the tank. This is a more efficient design than the idea of having it drain out of the bottom of the tank and through a slot in the milling table. Although it is more discrete to run a tube through the T-bolt slot, it is asking a lot of both the design and manufacturing teams to create a device that will actually align with the slot every time it is used. This could also have an effect on interchangeability to other machines whose milling tables may not be of the same dimensions. In this design, a preliminary box (tank) is welded out of standard 1/8” sheet metal. Once the box is welded together, two pieces of angle iron are to be welded on for the purpose of mounting. Both of these pieces of angle iron have slots milled in them to house the T-bolts that will mount them to the milling table. One of the pieces of angle iron (in this case the one on the right) will have a hole drilled in it that shares approximately the same center as the hole out of the drainage coupling. A hose will be run from the drainage coupling and out the hole in the side (that will be sealed with an industrial sealant) and to a sump pump that will pump the dielectric fluid back into the tank. This is NOT a final design. As of right now, some changes may still have to be made. One such change may be that the height of the coupling is unacceptable. This is just a concept design that will be brought up to Robert for his approval or disapproval.

The part drawings of the components in this device are (Angle iron, angle iron w/hole, drainage coupling, work tank, assembly one, assembly two, and the welding assembly). The following models were made for this project: Angle iron w/ hole, angle iron, drainage coupling, work tank, T-bolt, assembly 1, and assembly 2. I also created a design guide for the project.

Upon further communications, I found that I was mistaken in the design that was being requested. Instead of having the coupling as the drainage device, I was supposed to use a standpipe that drains into and through the coupling. At this point, I had a standpipe designed from my first concept and all I had to do was edit the size and shape of both the standpipe and the coupling. After altering the size and shape of these two parts, I edited their fully dimensioned and documented drawings. I then modified the assemblies and their drawings. (Coupling, Standpipe, Assembly one-2, Assembly two-2). Images: Standpipe, Coupling, Assembly one-2, Assembly two-2.

 

 

This image reflects the changes that were made to the standpipe and coupling, as well as the assembly of all of the components.

 

After I finished designing the work tank, Robert approached me to ask if I would take part in the design of the EDM head assembly as well. I told him that I was more than willing to help him out with the design. He provided me with some hand-drawn mechanical drawings with roughly the dimensions and design that he had in mind. He also told me to keep in mind that the design was open for debate and modification.

 

 

 

After looking over the drawings, I modeled them and then produced the part drawings. Once I got the drawings and models completed, I began to dimension. In my dimensioning I noticed a potentially hazardous design flaw. The fact that the minimum reasonable tolerance for drilling is 0.010” gave a lot of room for error on the holes for the guide rail, in the top and bottom plates. This meant that in the worst case scenario, there could be at least 0.020” difference between the hole centers. This would have posed a serious problem for the guide rail system, because the sliding plate might have faced restriction in sliding under those circumstances. The solution to this problem was to remove the counter bore from the bottom plate and leave a lot of clearance between the hole and the mating guide rail. This would make it so that the location of the top plate holes would be critical but there would be more room to miss the location of the bottom plate holes. When the device is assembled, the holes in the top plate will be used to locate the guide rail to where it needs to be tightened to the bottom plate so that the rails are vertical and parallel. After I (with a little help) noticed this design flaw and solution, I implemented design changes to fix the problem. After trouble shooting the design, these were the final models and drawings that I came up with:

Models

Drawings

Standard Components

Bottom Plate

Bottom Plate

10-32 Hex Nut

Bushing

Bushing

Washer

Guide Rail

Guide Rail

 

Lead Screw

Lead Screw

 

Sliding Plate

Sliding Plate

 

Top Plate

Top Plate

 

Head Assembly

Head Assembly

 

Stepper Motor

(Top Left Isometric View)

(No Drawing Necessary)

 

 

Stepper Motor

(Bottom Right Isometric View)

(No Drawing Necessary)