Week 5:- Rest Unit & Clamp Unit Design Challenge

DESIGN OF CLAMP UNIT

INTRODUCTION

A Clamp unit is a unit designed to clamp/hold the car panel with NC blocks/ Mylars/ Rest by using a pneumatic clamp cylinder.

The parts of clamp unit are:

1. Rest block /Mylar
2. L - block
3. Shim / spacer
4. Blade or Adapter plate
5. Riser.
6. Clamp Arm
7. Pneumatic cylinder

FUNDAMENTAL OF CLAMP UNIT:

1. Take a section at PLP either in clamp opening direction or normal direction. Sections should be normal to base. Panel section through X, Y or Z direction passing through PLP.
2. The section will help in finalizing the shape of the clamp and rest block. Most importantly used for the finalization of gun shape.
3. Finalization of a base plate plane – consider the following things before deciding the base plate. Height of maximum and minimum weld spot from the floor. No gun arm should touch the base plate. Operator ergonomic while accessing all the spots.

CONSTRUCTION OF REST BLOCK:

1. If standard Mylar has to be used (Few companies make standard height and length of steel blank with few holes and dowels for clamping) then select the proper blank size as per the requirement; consider 5 mm above the panel.
2. As per your company or OEM, Tier 1 standard uses the different standards mounting risers. 3. Do not forget to add the 5mm shim. If you are combining rough locator or part sensor bracket along with the rest unit.
3. Take necessary care means a distance of rough locator from the panel. In the process of manufacturing, we use Steel Aluminum, S-grun, and Plastics. And hardening is necessary in manufacturing Mylar and Pin.

OBJECTIVE

The objective of the current project is to design and model two types of rest unit and three types of clamp units along with clamp arm, clamp cylinders, blocks, shims, blade and riser in CATIA software.

DESIGN METHODOLOGY

1. The project is titled with the “P001_Z03_ST010_03_00”. All the parts in the feature tree of the CATIA must follow the same process for easy identification of parts in the assembly.
2. The standard pneumatic cylinders are copies and pasted into the project folder. These files are downloaded from Tunkers website.
3. 
4. The L- blocks / Mylars / Rest blocks are modelled in such a manner that there won’t be any movement of car panel in the transverse direction. The clamp unit restricts the transverse direction translation and rotation.
5. 
6. Clamp arm is a bought out part, to which all the movalble parts are fixed. In general a clamp arm is apart of clamp cylinder. Clamp arms are different for different bore of cylinders. Clamp arms are available in different hole patch. Clamp arm are available as: Middle arm – A10, Right arm – A11, Left arm – A12.
7. A 5 mm space is provided between the clamp arm and mylars as the shims or spacer blocks are present.
8. 
9. The dowel holes are present in all the parts of the pin units which are to be assembled with tolerance should be designed with 2 dowels and at least of 1 to 6 threated / free hole(depends on size). And to be fine machined for the mounting surface with 3 to 5 mm step machining.
10. Clamp cylinder is a pneumatic device works with pressurised air. The clamp cylinder is used to open and close the parts fixed to the clamp arm fixed to the clamp body. Clamp cylinders are in general 40,50,63 and 80 bore capacity. Opens up to 135° for horizontal clamp mounting. Opens up to 105° for vertical clamp mounting.
11. The riser is a part on which all the parts of a unit are mounted, and is mounted on the base plate of a tool. In general, the riser can either be make part or a standard part.
12. 

CONCLUSION:

The clamp unit with different Rest blocks, risers, clamp arms and clamp cylinders are modeled and designed in the CATIA software. If the company has some standards it is advised to use that standard for the rest blocks. It si advised to use as many as standard parts so it will be easier for the manufacturer to fabricate the fixture.