Boots – shoes – and leggings
Patent
1988-11-02
1991-01-22
MacDonald, Allen R.
Boots, shoes, and leggings
356347, G01B 902
Patent
active
049875450
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for monitoring the manufacture of a product, and more specifically, although not exclusively, for monitoring the possible occurrence of undesirable changes in shape or deformation of a manufactured product.
BACKGROUND PRIOR ART
The problem of estimating or measuring the change in shape, or deformation, of a manufactured product is one of a general character. There is today a general need to estimate or measure the change in shape or deformation of a product under manufacture, so that when carrying out prototype checks it is possible to anticipate what constructional changes, e.g. tool changes, will be needed and so that when carrying out production checks (quality checks) the need for taking rectifying measures, e.g. tool replacement because of worn tools, can be both observed and put into effect at an early stage, thereby greatly reducing the number of faulty goods which need to be rejected, if not avoiding the occurrence of rejects altogether, particularly when the product is manufactured in large numbers.
The problem of measuring or estimating the deformation or change in shape of a product is particularly prevalent in products produced from polymeric materials, due to the anisothropic properties of the injection moulded products; even though measurements are taken at given points, no definite knowledge can be obtained of the circumstances prevailing at the points therebetween. In addition, because the material is resilient it can readily be deformed or blemished by contact with gauges, templates, measuring probes etc., when the product is measured for distortion by means of a conventional contact method. Certain products are used normally in a humid atmosphere, and hence the lack of a practical method of measuring moist products is a distinct disadvantage.
SUMMARY OF THE INVENTION
The object of the present invention is to eliminate these drawbacks. Accordingly, the present invention consists in a method for monitoring the occurrence of possible changes in shape of a manufactured product, comprising producing a series of images of the product at pre-determined intervals of time, by means of holographic measuring apparatus, in a manner such that the images at each imaging time point are representative of possible deformation in the product in relation to the immediately preceding imaging moment; evaluating the rate at which such deformation occurs in time, from the images thus produced; and extrapolating the values relating to the rate of deformation so as to obtain the final value of the deformation of the product relative to the form or state of the product immediately subsequent to the time of its manufacture.
These and other features of the inventive method are set forth in the following claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with reference to the accompanying drawing, in which
FIG. 1 illustrates a number of curves showing the rate of progressive deformation of a product as a function of time (e.g. warping, shrinkage); and
FIG. 2 illustrates the interference pattern of a hologram produced from a plastic product.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
When developing and manufacturing new plastic products it is preferable to obtain, as early as the prototype stage, an understanding of how the new product will behave after leaving, e.g., the injection moulding tool; this is necessary in order to make at an early stage those constructional changes required in order to avoid the occurrence of rejects further on in the manufacturing chain, such rejects being caused for example by unacceptable distortion of the product, stress concentration in the product material, etc.
To this end the product is first cooled rapidly to normal room temperature, which can be effected in approximately 10 minutes. A series of images of the product, or optionally a specific part thereof, are then produced at predetermined time intervals with the aid of holographic measuring apparatus. In this reg
REFERENCES:
patent: 3911733 (1975-10-01), Bhuta et al.
patent: 3934461 (1976-01-01), Heflinger et al.
patent: 3938889 (1976-02-01), McKinnis
patent: 4304458 (1981-12-01), Huignard et al.
patent: 4464052 (1984-08-01), Neumann
LandOfFree
Method for monitoring the manufacture of a product does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for monitoring the manufacture of a product, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for monitoring the manufacture of a product will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1559053