adaptive repair for remanufacturing
TRANSCRIPT
The principal aim of this project is to develop a methodology and
its associated algorithm to prepare the component for repair and
to automatically identify the welded part of the repaired geome-
try to enable adaptive machining for creating a smooth surface
finish for the geometry.
The objectives of this project are to:
1.1.Review and analyse the state of the state of the art of re-
manufacturing to understand the concept.
1.2. Develop a methodology for the generation of customised
tool steps by creating a programming algorithm for smooth sur-
face and the preparation for testing using MATLAB.
1.3. Demonstrate and verification of the proposed methodology
by using a 3D printed part.
Summary Remanufacturing is comprehensive and challenging industrial
procedure to bring defective part which have failed due to fatigue
back to use. The process is currently done manually, this is time
consuming, hence the need for adaptive repair. A good surface
finish should have a theoretical surface between finish 1.6 and
3.2 µm
The 3 mains Methodology for adaptive repair
Preparation of the surface of an unknown defective part ge-
ometry for repair
Comparison of geometry with a defect with the original ge-
ometry
Generation of G-code for welding
Fill up material with weld
Creating a smooth surface after welding
Develop algorithm to create tool path
Generate G-code which is used for CNC machining process
3. CYLINDRIC VS PRISMATIC
SHAPE Most rolling stock components are cylindrical in shape e.g.
crankshaft /drive shaft.
A turning operation is needed to improve the surface finish on
shafts
The typical machining or cutting parameters for shafts are
Depth of cut, Cutting feed and Feed rate
Rolling stock components are usually prismatic shaped
A milling operation is needed to improve the surface finish
An endmill or ball nose cutter is often used
The machining parameter include spindle speed, cutting
speed, feed rate, number of tooth.
1. AIMS AND OBJECTIVES
2. BACKGROUND
4.2. COMMON ROLLING STOCK MATERIALS
Material End mill cutter (6mm diameter)
Turning tool
Cutting speed (m/min)
Feed per tooth (mm)
Cutting speed (m/min)
Feed rate for fine machining
Mild steel 30 – 40 Roughing cut
= 0.020
Finishing cut
= 0.039
120 - 200 0.03 – 0.1
Cast iron 18 – 25 80 – 140 0.05 – 0.2
Aluminium 50 – 110 80 – 1200 0.05 – 0.5
Stainless steel
10 - 15 140 – 190 0.02 – 0.6
Brass 30 – 50 300 - 1000 0.01 – 0.2
TABLE 1: Displaying the cutting parameter
4.1. CUTTING PARAMETERS FOR MACHINING
Designation Abbreviation Unit formula
Spindle speed n RPM n=( vc ×1000)/
(d × π)
Cutting speed Vc m/min Vc =(d ××n)/
1000
Feed rate Fr mm/min Milling
Fr=fr × Z× n
Turning
Fr=fr × n
Theoretical Surface finish
Ra µm Ra=(fr^2)/8R
Where Z = number of tooth/flute can be from 1, 2 or more Fz = feed per tooth (mm) R = radius of cutter (mm) d = diameter of work piece for turning and tool cutter diameter for milling
π = 3.14
A mild steel block of size 75mm x 60 x 30mm
A hole was cut out in the middle of the block.
The defective part was cleaned with an electronic flap disc.
A MIG (Metal Inert Gas) was used to weld the surface to about two
2mm high.
The block was taken to the CNC machine laboratory.
The block was modelled on Solidworks 2017.
The CAD model was transferred to SolidCAM software.
The software was setup for face milling. An 6 mm diameter end mill cut-
ter was used with the calculated feed rate of 248.28mm/min and the
spindle speed of 1591.55RPM
A simulation was run to see the tool path and GCode
The GCode was fed into the CNC machine which had milled off the
welded part off the block to create a smooth surface
5. METHODOLOGY
Turning operation
Material = aluminium
Diameter of shaft = 80mm
Spindle speed = (130 ×1000)/(80 × π) = 517.25 rpm
Feed rate = 0.1 x 517.25 = 51.73 mm/min
Milling operation
Material = mild steel
Diameter of endmill cutter = 6mm
Spindle speed = (30 ×1000)/(6 × π) = 1591.55 rpm
Feed rate = 0.039 x 4 x 1591.55 = 248.28 mm/min
Feed rate per revolution = 0.039 x 4 = 0.156 mm/rev
Ra = 〖0.156〗^2/(8 ×3)=1.014×〖10〗^(-3) mm
Unit conversion: 1mm = 1000 µm
Ra = 1.46 ×〖10〗^(-3) ×1000=1.46 µm
5.1 STRATEGY FOR G-CODE
1.Create a text file
2.Identify the coordinate of the geometry
3.Determine the start as finish location based on the area of the re-
paired surface.
4.Calculate the cutting parameters such as feed rate and spindle
speed.
5.Manually write the necessary M and G codes.
6.Develop an algorithm on MATLAB.
7.Set variables as codes and then Generate G-code.
9.The G-Code should generate automatically in the text file.
5.2. STRATEGY FOR TOOL PATH
6. VERIFICATION
7. CONCLUSION
The process of developing an algorithm for the adaptive repair for
smooth surface has been successful.
However, the verification process
The theoretical roughness for the milling process is below the threshold
of 1.6 and 3.2µm
The factors that affect the smooth include the feed rate, chip load, spin-
dle speed and number of cutter tooth.
For this case the number of tooth Z can be 5, therefore the recalculated
Ra would be 1.6µm
8. FURTHER WORK
Another verification is to be carried out with a 3D printer.
Due to time and the volume of work involved in this project, more
work needs to be done on the preparation of the surface for mate-
rial deposition.
9. REFERENCES
•Table 1 was sourced from WNT Mastertool “Total Tooling” catalogue
•https://smithy.com/machining-reference/lathe-turning/page/2
18/04/18
ADAPTIVE REPAIR FOR REMANUFACTURING
BY OSATO OSEMWENGIE
13419381
4. THEORY
Figure 2: mild
steel with defect
Figure 3: welded
surface
Supervisor: Dr Wang
Internal Examiner: Mr Milne
Identify the boundary: since the geometry
for the repaired (welded) surface is known,
identify the start and finish point of the ar-
ea.
Create an area on the matlab as Xmax,
Xmin, Ymax , Ymin, Zmin and Zmax
Create a point cloud with the coordinates
and another point cloud with the a varia-
ble.
Determine the tool path width, number of
tool steps set this as variables on MATLAB
Generate the tool path automatically
Figure 1: Framework of methodology, the parts highlighted in green
where this project started from and ends in yellow.