The ends of the arms, or 'temples' of cellulose acetate eyeglass frames must be trimmed near the hinges to a very high precision to fit the frame fronts. This process is traditionally done piece-by-piece, a laborious process with a high error rate. This machine can trim temples in batches of 12, speeding the process and reducing handling errors.
The joint between the temple-piece and the front-frame is essentially a miniature compond-mitre butt joint, ideally closing flush. As any carpenter will tell you, this is an almost impossible joint to execute perfectly in any material, as both planar mating surfaces of the joint must meet at a single plane. Add to this the comparatively enormous lever arm of the temple-piece, and a deviation from perfection of more than 0.02mm in the location of either joint surface results in unacceptable misalignment of the temple.
In short, the cut on both the front and the temple must be nearly perfect or the entire eyeglass frame becomes unusably warped.
In traditional eyewear manufacture, the temple/arm component is so cheap to manufacture to this point that errors in this cutting process can be discarded. At Tzukuri, temples at this stage of manufacture have expensive electronics permanently encapsulated within them. So each mistake here is unacceptably expensive, but the labour involved in cutting and fitting each individually by hand is possibly more so.
This machine was designed to allow the compound mitre to be set, reliably and repeatably, to a working tolerance of ± 0.02mm and ±0.25°, and to eliminate sources of error introduced by individual handling. Since the implementation of this machine, this tricky process has become one of the most reliable processes in the Tzukuri production set.
In short, the cut on both the front and the temple must be nearly perfect or the entire eyeglass frame becomes unusably warped.
In traditional eyewear manufacture, the temple/arm component is so cheap to manufacture to this point that errors in this cutting process can be discarded. At Tzukuri, temples at this stage of manufacture have expensive electronics permanently encapsulated within them. So each mistake here is unacceptably expensive, but the labour involved in cutting and fitting each individually by hand is possibly more so.
This machine was designed to allow the compound mitre to be set, reliably and repeatably, to a working tolerance of ± 0.02mm and ±0.25°, and to eliminate sources of error introduced by individual handling. Since the implementation of this machine, this tricky process has become one of the most reliable processes in the Tzukuri production set.
The temple trimmer was designed to be cheaply machined from flat aluminium and POM stock, with standard hardware. Toolpaths were selected to minimise the need to change workholding. A screwed wedge between the two plates sets the angular adjustment. Depth of cut adjustment, trimming blade, and front-frame trimming attachments not shown.
