Advanced processing of additively manufactured parts (AdProcAd). (AdProcAdd)

The Ad‐Proc‐Add project aims in the systematic and comprehensive investigation of additive‐subtractive manufacturing (ASM) process chains in order to achieve a detailed understanding of influences and interdependencies of parameters, strategies and boundary conditions with respect to the material and workpiece properties of additively manufactured (AM) and post‐processed parts in various applications.  The research work of the Flemish project partners (KU Leuven, Thomas More, BIL and Sirris) is focussed on a process chain based on robotised WAAM, combined with mechanical cutting (etc. milling, drilling, etc...)

The additive-subtractive manufacturing (ASM) process chain was investigated for parts produced by WAAM (Wire Arc Additive Manufacturing). The optimal production planning method was developed and evaluated on the various case study parts. To provide the guidelines for the Flemish industry, 3 webinars were created. Each seminar gives the theoretical background and step-by-step explanation of the procedure for the selected case study part.

The first workshop/webinar focuses on the Wire and Arc Additive Manufacturing. It covers the deposition path planning for WAAM, programming of the welding robot, setting-up the welding robot and welding power source for the WAAM and finally deposition. The webinar can be accessed through the link: https://youtube.com/playlist?list=PLR65B4SgaCKBD36-fTKgan3p0yQCoqHki

The WAAM parts are characterised by low dimensional accuracy and low as-deposited surface quality (i.e., the waviness is around 0.5 mm). Additionally, the heat induced during the deposition process causes the distortions of the substrate plate. This leads to high positioning and alignment errors during post-processing resulting in unsatisfactory part quality. It was concluded that intermediate processes such as substrate pre-machining and 3D scanning of the part are required. The second webinar devoted to the intermediate processes was created. It covers such aspects as 3D scanning, CAD model fitting and alignment, preparation of the part for future programming of the machining step in CAM: https://youtu.be/mToCJ2-Fr4M

The third webinar is devoted to the post-processing of the WAAM part (i.e., milling). It covers the preparation of the model for programming of the machining step in CAM, tap testing, selection of the milling parameters taking into account the dynamic behaviour of the process (i.e., stability lobe diagrams) and machining using the NC machine tool. The webinar can be accessed through the link: https://youtu.be/V4PSYYdA6fk.

The multi-sensor platforms were developed separately for the AM and post-processing steps to investigate the impact of different processes on the characteristics of the final part. Various demonstrator cells were developed and are opened for the Flemish companies.

KU Leuven together with Thomas More have two demonstration cells for WAAM in campus De Nayer (Jan Pieter de Nayerlaan 5, 2860 Sint-Katelijne-Waver). One demonstration cell includes the CLOOS QRC320H robot cell with a 2-axis positioning table and Qineo pulse 450A welding power source. The second demonstration cell also includes a ABB robot cell (IRB 1600-10/1.45) with a 2-axis positioning table and Fronius TPS 500i PULSE power source. Both demonstration cells are equipped with sensors to monitor current, voltage, gas flow rate and temperature. Additionally, 3D scanners (laser and structured light) are available to perform the intermediate steps and quality control of the final products.

KU Leuven provides the demonstration cell for the WAAM parts milling. The milling is implemented on the 5-axis milling machine DMG DMU 50. The techniques used for monitoring the milling process include the use of dynamometers for force measurement, proximity sensors for vibrations monitoring and sensor to monitor the contact between the workpiece and a tool to assess the analysis of the vibrations during the milling of the thin-walled part. The demonstrator cell is located at Campus Arenberg (Celestijnenlaan 300, 3001 Leuven).

The Belgian Welding Institute (BIL- Belgisch Instituut voor Lastechniek) has a demonstration cell for WAAM. The demonstration cell includes the KUKA type KR8 R2010 welding robot, 1-axis positioner and Fronius CMT welding machine. The monitoring platform contains the following sensors: the current, voltage and wire feed speed sensors, acoustic emission, IR camera for temperature measurement, spectroscopy, and high-speed camera. BIL supports companies that want to take steps towards WAAM additive manufacturing of metals; from feasibility studies to integrating the technology into the production environment. The demonstrator cell is located in Belgisch Instituut voor Lastechniek vzw. Technologiepark-Zwijnaarde 48 (Tech Lane Ghent - Zone A2), 9052 Zwijnaarde (Gent), België.

Sirris provides the demonstration cell for post-processing of the WAAM parts. To implement the machining, a high precision 5 axis milling machine, Fehlmaan Picomax 825 was used. The in-process monitoring is performed using the accelerometers and acoustic emission sensors. Additionally, at Sirris, the optimization of the milling parameters can be implemented using the stability lobe diagram and impact hammer testing to avoid the vibrations and increase the material removal rate. The simulation of the machining process is done using Cutpro software, which allows to consider the dynamic stability of the cutting process. Moreover, the 3D scanner (Creaform Handy scan) is available to perform the intermediate steps and quality control of the final product. The demonstrator cell is located in Wetenschapspark 9, 3590 Diepenbeek.