Type of action (RIA or IA) RIA
Programme Area AIR
Joint Technical Programme (JTP) Ref. WP A-3.3 Indicative Funding Topic Value (in k€) 500 k€
Duration of the action (in Months) 36 months Indicative Start Date27
Q1 2017
Identification Title
JTI-CS2-2016-CFP03-AIR-01-17 Orbital Drilling of small (<10mm diameter) holes, standardly spaced with aluminium material in the stack
Short description (3 lines)
There are two lines of research proposed in this call, both related to the development of orbital drilling. The first is to introduce residual stress when drilling in aluminium, this is seen as the main reason orbital drilling is not more widely used in the aerospace industry. The second is to enable drilling of smaller holes positioned closer together (a limitation with existing machines/methods).
CfP03 Call Text 177
1. Background
This topic is part of Airframe High Performance and Energy Efficiency (Activity Line A) and more specifically is defined in Work Package (WP) A-3.3: Innovative shapes & structures.
Aircraft structures such as cargo doors can be fairly complex products and a typical cargo door can consist of hundreds of individual parts which need to be assembled together. Orbital Drilling is well established within the aerospace industry and has provided excellent results for larger holes with stacks containing typically a combination of carbon fibre, titanium and steel.
Orbital drilling can be seen as a combination of milling and drilling, a cutting tool that is smaller than the planned hole diameter revolves around its own axis with pressure against the surface while orbiting to create the hole diameter. Benefits of orbital drilling include burr free holes, reduction in number of drill bits (diameters) required in production, larger repeatability and no need for cooling liquid. The risk for poor quality holes is minimal and it is a clean drilling method with efficient removal of drill chips and dust.
Automated drilling solutions will be crucial to increase the competitiveness of the European aerospace industry; reducing manufacturing costs whilst reducing the likelihood of rework or scrap parts due to drilling operation errors. In addition, current production lines which were built on technologies available many years ago do not always use solutions which would be chosen with today’s knowledge and technology. Automated orbital drilling has the potential to significantly reduce production time and cost for both new and current production lines.
There are at present only a handful of products on the market for orbital drilling, and none of these machines offer a solution for aluminium, nor for tightly spaced holes. Recent research has revealed that there is a struggle to achieve the same benefits from orbital drilling in aluminium, as in titanium and carbon fibre. Compared to conventional drilling a lower but more controlled force is applied against the processed surface providing lower residual stress when compared with traditional drill and ream procedures, this is an issue for aluminium where the residual stress provides better fatigue resistance. It is of great interest to overcome these issues as aluminium is an important material used in the aerospace industry. A series of proposals have been made in recent research projects, and one of the objectives with this call is to develop and evaluate these proposals.
Within Work Package A-3.3 the development of a new state-of art orbital drilling unit for drilling small holes in aluminium, in combination with a suitable method to drill smaller holes in close proximity to each other, is proposed. The drilling unit shall be light enough to be handled both by an operator and a light weight industry robot (paving the way for a fully automated solution). It shall also ensure that there are no burrs between stacks until the installation of fasteners can be conducted, thus paving the way for one-way assembly. Furthermore the topic is also to investigate how orbital drilling in aluminium alloys should be conducted, in order to attain residual stress in the
CfP03 Call Text 178 material surrounding the hole.
This document describes the indicative work structure, a general time schedule, the expected deliverables and the general requirements that shall be considered for the selection of an appropriate partner.
Figure 1. Typical assembly where orbital drilling could offer substantial benefits over traditional drilling methods
2. Scope of work
The activities planned for this call will result in the demonstration of residual stresses in aluminium when drilling small (<10mm diameter) holes with standard spacing, suitable material stacks containing aluminium shall be used. This will be performed through investigation, concept study and the design and production of a prototype for a suitable Orbital drilling unit.
The call is split up into the following work packages (WP): Work Packages
Ref. No. Title – Description Due Date
WP 1 Investigation of orbital drilling in aluminium alloys T0+18 WP 2 Orbital drilling unit capable of drilling smaller holes (<10mm) standardly spaced, in various airframe material, including aluminium and hybrid joints T0+36 WP 3 Verify and demonstrate the functionality of the prototype T0+36
WP1 – Investigation of orbital drilling in aluminium alloys
Orbital drilling has shown great benefits in material such as composites, titanium and steel. The objective of this WP is to introduce residual stress in stacks containing aluminium.
An investigation of orbital drilling in aluminium alloys used in aero structures has to be performed in order to study the factors altering the properties of the material. Finite Element Analysis (FEA) and simulations shall be used as first attempts to investigate the sequence of events occurring during the drilling operation in aluminium alloys. Following the computer aided analyses; physical samples shall