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TNO is building EBL2: a laboratory EUV exposure system capable of operating at high broad band EUV powers and intensities, in which XPS analysis of exposed samples is possible without breaking vacuum. Its goal is to accelerate the development and testing of EUV optics and components by providing a publicly accessible exposure and analysis facility. The system can accept a range of sample sizes, including standard EUV reticles with or without pellicles. In the beam line, EUV masks and other samples can be exposed to EUV radiation in a controlled environment that is representative of actual operating conditions. This contribution will describe the design of the EUV beam line.

Aspherical and freeform optical elements have a large potential in reducing optical aberrations and to reduce the number of elements in complex high performance optical systems. However, manufacturing a single piece or a small series of aspherical and freeform optics has for long been limited by the lack of flexible metrology tools. With the cooperative development of the NANOMEFOS metrology tool by TNO, TU/e and VSL, we are able to measure the form of aspheres and freeforms up to 500 mm in diameter with an accuracy better than 10 nm rms. This development opened the possibility to exploit a number of iterative, corrective manufacturing chains in which manufacturing technologies such as Single Point Diamond Turning, freeform grinding, deterministic polishing and classical polishing are combined in an iterative loop with metrology tools to measure form deviation (like CMM, LVDT contact measurement, interferometry and NANOMEFOS). This paper discusses the potentials, limitations and differences of iterative manufacturing chains used by TNO in the manufacturing of high performance optics for astronomical purposes such as the manufacturing of the L2 of the Optical Tube Assembly of the four laser-guide star facility of the ESO VLT, Manufacturing of Aluminum freeform mirrors for the SCUBA-2 instrument. Based on these results we will give an outlook into the new challenges and solutions in manufacturing high-precision optics. © 2012 SPIE.

For years now conventional aluminium 6061 T6 has widely been used for mirrors in astronomical instruments, being diamond turned or since a few years also being optically polished. This allows the development of optical systems that can be tested and operated at any temperature, without being affected by CTE effects. Using traditional aluminium the manufacturing methods could in some cases not deliver the required surface shape, accuracy and roughness due to the increasing demands from optical systems. Over the last few years RSP Technology developed a new series of aluminium alloys for several applications, produced with a Rapid Solidification Process. Both on a macroscopic and microscopic level these new aluminium alloys have different material characteristics compared to the traditional aluminium alloys. TNO and NOVA-ASTRON have performed diamond turning and polishing tests on these new aluminium alloys. This paper presents results of several diamond turning and polishing tests obtained over the last year and show the potential of these new alloys with surface roughness values of 1 nm on RSA 6061 and RSA 708 acquired with both diamond turning and polishing. © 2012 SPIE.

In this paper, we discuss the two-mirror pushbroom telescope for TROPOMI. Using freeform optics, it has unprecedented resolution. The complete cycle of freeform optical design, analysis, manufacturing, metrology and functional test on a breadboard setup is described, focusing on the specific complexities concerning freeforms. The TROPOMI flight telescope will be manufactured in summer 2012.

Hier vindt u het boek over het verspanen van moeilijk bewerkbare materialen. Het is het resultaat van het TNO kennisoverdrachtproject “Verspanen van moeilijk bewerkbare materialen” Het bevat zowel achtergrondkennis als praktisch toepasbare richtlijnen en gegevens. Het is een introductie in dit onderwerp en kan ook gebruikt worden als naslagwerk. Aan de inhoud van dit boek hebben de volgende bedrijven bijgedragen: Cimcool Industrial Products BV, CNC Consult & Automation BV, Dijk Consult, Hamel metaal, Heidenhain Nederland BV, Hembrug BV, Oerlikon Balzers Coating Benelux, Seco Tools Benelux, Techno Trade. Daarnaast is bij de totstandkoming ook gebruik gemaakt van andere bronnen. Het project is uitgevoerd door TNO in samenwerking met de Koninklijke Metaalunie, het FME-CWM, Syntens, negen verspanende bedrijven en elf toeleverende bedrijven. Dit project is gesponsord door het Syntens Applicatie Centrum Productietechnologie (ACP) en de regeling TNO MKB Kennisoverdracht van het Ministerie van Economische Zaken (EZ).

One of the applications of the micromilling technology is to machine micro features on moulds by direct machining of hardened tool steels. However at this moment, this process is not industrial applicable because of the encountered problems, such as the big tool deflection, severe tool wear, and pre-mature tool breakage. A detailed examination of current commercial micro endmills showed that the geometry of micro endmills is mainly derived from macro endmills, which has been proved to be not suitable for micro hard milling application in experiments. Based on the experimental observations, the guidelines for the design of micro endmills for the micro hard milling application were generated. These guidelines were applied in the re-design of the micro endmill with the help of analytical modeling and Finite Element Analysis. The main purposes of the new design are to increase the strength of the cutting edge corner of the micro endmill and to improve the micro tool stiffness. The preliminary experiments with the new designed endmills showed that the new geometry has improved the tool performance largely.

Surface roughness is a key parameter in evaluation of engineering surface in macro scale; in case of micromilling, it is of even greater importance because the magnitude of the roughness can be comparable with the workpiece tolerance, and will have a direct impact on the quality of the microproducts. This paper presents the preliminary results of experimental investigations on micromilling process. In this study, the influence of machining parameters on the surface roughness in micromilling was studied and compared with the observations in former researches. Besides, it was found that in microscale the roughness is largely influenced by the tool runout; runout has the effect to increase the effective feed per tooth. For conventional milling, roughness can be used for tool wear criteria; however in the experiments, no obvious relation was found between wear of micro endmills and workpiece surface roughness.

This paper discusses the influence of runout on the calculation of the coefficients of mechanistic force models in micromilling. A runout mode is used to study the change of chip thickness, tool angles, and immersion period of two cutting edges of micro endmills due to runout. A new method to find the cutting coefficients was proposed based on the observations.

Proper setting of cutting conditions is critical for the performance of micro endmills in micro milling of hardened tool steels. In this paper, the influence of the cutting parameters on the wear behaviour of micro square endmills is presented. The selected parameters are cutting speed, depth of cut, and feed per tooth; Central Composite experimental Design (CCD) was used for a statistical analysis of the influence of these parameters. A quadratic model was fitted to describe the performance of the tool wear; the ANOVA analysis shows that the quadratic model gives a good prediction of the experimental results. On considering the magnitudes of the coefficients it is seen that the feed per tooth has a greater influence on the tool wear than cutting speed and depth of cut within the tested process window. By applying this method, the micromilling process can be planned to achieve an optimum tool wear performance for a tool-workpiece combination.

In experimental investigations of micro milling of hardened tool steel SAE H11, with a hardness of 56 HRC, with commercially available micro square endmills of Ø 0.5mm, it was observed that the endmills suffered from severe tool wear/failure. Because of these problems, the quality of the machined workpiece was not satisfying, in terms of burr formation and form accuracy. By analyzing the results, it is concluded that the current endmill geometries are not suitable for micromilling, which are mainly derived from macro endmills. Based on these observations, the design guidelines for micro endmills for micro hard milling application were generated. The tool geometries are improved by means of analytical and FEM analysis. Micro endmills with new designed geometries were manufactured and validated through experiments. The results showed that the new endmills had a tool life about 6 times longer than the endmills with original design; accordingly, the workpiece quality was also improved significantly.

Due to the scaling effect, micro endmills have low stiffness in nature, which will result in lose of form accuracy in workpiece and vibration of micro tools during micromilling process. Through analytical modeling, it is found that the neck geometry of the micro endmill has a big influence on the tool stiffness; therefore it is important to improve the neck shape to achieve a high stiffness. In this paper, five different types of neck geometries were studied first by mathematical models, and then tested by Finite Element Method (FEM) to see their influence on the tool performance. Based on the modeling results, the micro endmill geometry was re-designed; micro endmills with new geometries were manufactured and tested in experiments. The experimental results showed that the new neck geometry has higher stiffness compared with the neck geometry used in commercial endmills.

In the recent years the interest in loose abrasive machining processes as efficient, flexible processes is rising. This paper describes the development of a ‘coherent set of models’ for a category of these processes, namely those which use high velocity of the particles to obtain the necessary energy to machine a workpiece surface. The usability of this ‘coherent set of models’ will be explained with its application in the field of high-pressure abrasive waterjet cutting. At the end of this paper a forecast to the application of this modelling technique to other loose abrasive machining processes as Micro-Abrasive Air Jet Machining is given.