Machining photochemical

Corning 8603 lithium metasihcate, Li2OSi02 Hthium disiHcate, Li2 0-2 Si02 photochemically machinable fluid amplifiers... 

Packaging (paper and plastic) packaging adhesives release coatings barrier coatings Photochemical machining (89) micromechanical parts optical waveguides... 

A further variation of this technique, developed in the late 1950s, led to etching completely through the metal plate to produce thin metal parts. This fabrication method is now known as photochemical machining or PCM (Allen 1986). 

Photochemical machining Photoresist or (PCM) silk screen Conductors, polymers, glasses, and ceramics mm -10 m High (pm-mm)... 

Allen DM (1986) The principles and practice of photochemical machining and photoetching. lOP Publishing, Bristol, p 4... 

Allen DM (1993) Progress towards clean technology for photochemical machining. CIRP Armais 42(1) 197-200... 

Allen DM (2004) Photochemical machining from manufacturing s best kept secret to a 6 billion per annum, rapid manufacturing process. CIRP Annals... 

Light-Driven Rotaxanes Incorporating a Photosynthesiser - Towards Photochemical Machines... 

Manufacturing Process. A master of the substrate is machined in copper by a UV laser or by photochemical machining. The vias are deep, and the circuits and pads are shallow. Since only one master tool, called aToolFoil, is required, time can be taken to make sure the master is perfect. With a laser, it is possible to have perfect registration of lands to via holes or even landless vias. This master is electroformed with nickel and back-filled to make a master tool. A sample ToolFoU is shown in Fig. 23.38. 

Ferric chloride solutions are used as etchants for copper, copper alloys, Ni/Fe alloys, and steel in PC applications, electronics, photoengraving arts, and metal finishing. Current use of ferric chloride etchant in printed wiring fabrication is extremely limited in the United States because of costly disposal of the copper-containing etchant, and the much better commercial support for ammoniacal and cupric chloride etchants. There is still considerable use for alloy etching and photochemical machining applications. 

ED photoresists are increasingly being successfully applied to photochemical machining processes in the manufacture of products such as colour TV receiver tube aperture masks (shadow masks), integrated circuit lead frames and printing rollers. These resists are used as etch-resists for a variety of metals and alloys, and can withstand the harsh etching conditions used in these processes. 

ED resists are relative newcomers to the printed circuit board and photochemical machining industries, and as yet have not been accepted as widely as the well-established techniques. However, as these techniques are increasingly pushed to their limits and ED resist technology continues to improve, the utilization of ED resists is expected to grow dramatically over the next few years. 

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