Description

Technical Field

The present development is related with Military Aviation. Industry more particular to structural assembly of Tejas (LCA) Aircraft.

Background of invention

For interchangeability of panel, it was proposed to make two different tool, one for drilling the fastener holes on the panel and the other for drilling the fastener holes on the structure.

The fastener hole axis on the parts involving complex profile and the axis were compound angle. If the (1) Drill Jig meant for drilling on the panel and (2) Drill Template meant for drilling on the Airframe structure is made separately using a metallic tool, there is a possibility of warpage and coordination between the holes made out of Tool 1 and Tool 2 is a matter of concern.

To overcome the problem of warpage of the Aluminum machined template and to avoid the effect of dimensional deviation at the time of 5 Axis Drilling on the Tool 1 and Tool 2, the method of common master for making the Tooll( Drill Plate meant for Drilling the holes on the panel) and Tool2(Drill plate meant for drilling the holes on the structure) is proposed.

Summary of invention

A master model is machined as per the inner profile of the component (Doors/ covers) Tool 1 is made by layup directly over the master model by transferring the hole position from the master.

Tool 2 is made by layup over the simulated component thickness over the master model.

Tool 1 is used for Drilling the holes on the Airframe structure and Tool 2 is used for drilling the holes on the panel.

Process details description

Tooll:- Method of making Drill plate for Structure:-

Step 1.: A master model is machined as per the inner profile of the door/panel which means the outer profile of the Airframe structure.

Step 2:- 5 Axis holes were drilled on the machined master for the fastener hole location of Dia 12 Hll and lug hole of 6H11 and a depth of 16 mm.

Step 3:- A pin of 12 g6 and a liner bush of Dia 12 H9- Inner Diameter and Dia 16 with serration as as OD is made.

Step 4:- A thin layer of releasing agent(Wax) is applied on the pin and the pin is inserted on the serrated bush and the pin is made such that it is projected out of liner bush by 12 to 15 mm.

Step 5:- The above combination of pin-bush is taken and the projected pin is inserted on to the hole made on 5 Axis machined master model where a thin layer of releasing agent(wax) was applied over the master model.

Step 6:- A glass cloth+ resin + hardener combination is used of laying up to 12 mm thickness and allowed it to cure for day.

Step 7:- Then the pins were removed from the above set up allowing the serrated bush got embedded on the layed up glass cloth.

Step 8;- slowly the layed up template is take out and it is be used for drilling holes on the Aircraft

Tool 2:- Method for making Drill plate for panel.

Step 1 to 4 :- same as above.

Step 5:- Simulator preferably out of Wax sheet or rubber sheet of the component thickness is pasted over the master with suitable holes at the fastener and lug hole position, then a thin layer of releasing agent (wax) is applied over the simulator, combination of pin-bush is taken and the projected, pin is inserted on to the holes made on the 5 Axis machined master model along with the simulator sandwiched between the master and the layup.

Step 6 and step 7:- As is like step 6 and 7 of Drill plate for structure.

Step '8:- slowly the layed up template is taken out and it is be used for drilling holes on the

CLAIMS

We claim that :-

1. This method ensures the interchangeability of the .panel by using two different tool for two mating parts.

2. Warpage related problem in the conventional metallic machined tool is eliminated by usage of this method.