Measurements of frames surfassagem
Article written by Paulus Maciel. All rights reserved. A major concern of the professional optical is on the final thickness of the lenses surfassadas requested the laboratory. Several aspects can influence this thickness, including: choice of frame, refractive index compatible with the recipe etc. items mentioned above are fundamental to obtain a perfect lens diameter to optimize the thickness of it, however, if measures of frame are not well taken, the result of the diameter will not leave in accordance with all the care you took preventive during the sale. surfassadas In order lens is necessary to note the work order value in millimeters of the bridge hoop and diagonal Vertical frame to reduce the diameter of the block in the right measure for optimization of the thickness of the final product.
Before talking about the practice of measuring the rim itself, I will name the instrument that may be primarily responsible for the measures barely made the ruler. Abro this topic inviting you to reflect with me: "If all measures are taken in the frame millimeters, that all rules are optical branch with scale in inches? "
According to my 12 years of practical experience in this matter, I can say that taking measured in millimeters with centimeter scale induces professionals to error at the time of recording the data in order, especially when the day is busy and he , by necessity, need to work faster. rule The second factor that leads many professionals to make mistakes is the position where the "zero" the scale starts on the instrument. Notice in the picture the first two rules where the scale starts after edge and the second scale that starts exactly on the edge. Danger Scale to get past the border, which is using the border to support the ruler in the frame, you will measure 1 millimeter to more than it should, since the "zero" starts after this support.
Measurements of the side frame, in both cases, using the edge as a support strip, we see that the first rule is zero after starting the edge of the frame. This action will cause the professional measure the horizontal rim with the most 1 mm.
the second rule, the "zero" scale is starting at the edge of the frame, so the horizontal extent of the rim is perfect.
You must be wondering "Oh, one millimeter more or less will not make a difference ...". Do not forget that the full measure of a hoop, you will position the edge of the ruler four different times where we 1mm over the bridge, 1mm more horizontally, diagonally over 1mm to 1mm larger and more upright; totaling 4mm more on his work order, enough to leave a thicker lens.
Several times I witnessed consumers buying lenses and keeping the same frames, where the new lenses were thicker due to incorrect retelling of the frame measures current client with inadequate ruler. At this point I want to make a suggestion. If you have in your store any rule that the "zero" starting after the edge of it, throw it out or use a utility knife to cut the space between "zero" and the edge of the ruler.
Another common error happens in the measurement of hoop placement is "zero" over the edge of the frame, so that you measure millimeters to more than it should.Measurement of a rim consists in measuring the horizontal, vertical and diagonal through the inner edges of the frame and not on the outside. To measure a ring in its inner edge, place the zero between the inner edge of the rim and the top of the lens. Pictured next to the text have the same ruler, but in the example above showing "zero" over the edge of the rim , which is incorrect, because it will give a result in millimeters larger than necessary. the example below, we have the "zero" placed on the inside edge of the rim, causing the measure to be perfect. Always an inner edge of the ring to another. Now we can leave for the explanation of each part of the rim to be measured. 1 - The horizontal rim is the largest horizontal distance between the inside edges of the frame, as shown below.
2 - vertical rim is the greatest vertical distance between the inside edges of the frame, as illustrated.
3 - As the bridge is the shortest distance between the inner edge of the frame corresponding to the OD and the inner edge of the frame corresponding to the OE, as illustrated below.
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| Optical ruler with scale in cm |
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| Start from scratch in optical rulers |
the second rule, the "zero" scale is starting at the edge of the frame, so the horizontal extent of the rim is perfect.
You must be wondering "Oh, one millimeter more or less will not make a difference ...". Do not forget that the full measure of a hoop, you will position the edge of the ruler four different times where we 1mm over the bridge, 1mm more horizontally, diagonally over 1mm to 1mm larger and more upright; totaling 4mm more on his work order, enough to leave a thicker lens.
Several times I witnessed consumers buying lenses and keeping the same frames, where the new lenses were thicker due to incorrect retelling of the frame measures current client with inadequate ruler. At this point I want to make a suggestion. If you have in your store any rule that the "zero" starting after the edge of it, throw it out or use a utility knife to cut the space between "zero" and the edge of the ruler.
Another common error happens in the measurement of hoop placement is "zero" over the edge of the frame, so that you measure millimeters to more than it should.Measurement of a rim consists in measuring the horizontal, vertical and diagonal through the inner edges of the frame and not on the outside. To measure a ring in its inner edge, place the zero between the inner edge of the rim and the top of the lens. Pictured next to the text have the same ruler, but in the example above showing "zero" over the edge of the rim , which is incorrect, because it will give a result in millimeters larger than necessary. the example below, we have the "zero" placed on the inside edge of the rim, causing the measure to be perfect. Always an inner edge of the ring to another. Now we can leave for the explanation of each part of the rim to be measured. 1 - The horizontal rim is the largest horizontal distance between the inside edges of the frame, as shown below.
2 - vertical rim is the greatest vertical distance between the inside edges of the frame, as illustrated.
3 - As the bridge is the shortest distance between the inner edge of the frame corresponding to the OD and the inner edge of the frame corresponding to the OE, as illustrated below.
4 - The height is the pupillary distance in millimeters between the marking point and the lower edge of the frame.
5 - the diagonal is the largest diagonal distance between the inner edges of the frame. Pay attention to know which diagonal of the rim is the greatest, from left to right or right to left. See illustration
The excellent illustrations above, I got through the website of Hoya, if you want to download the complete guide of taken measures, CLICK HERE.
The last two tips are:
- Never add 2mm as a safety margin in order, because all programs that calculate diameters in these laboratories already added 2mm. If you put 2mm more in some measure, the system will understand that any laboratory is 4mm. The diameter fai get bigger and thicker lens.
- Avoid bending the strip during the measurement of the rim, since this action may result in higher measures than necessary.If you can, remove the lens demo (demo lens frame) draw it on a white paper and make measurements with a ruler in lens design on paper and not in the frame, with the exception of the bridge height and pupillary course .
Taking all these precautions, I'm sure you will get good manual measurements of the frames to lenses surfassadas request. The diameter is made as small as possible and optimal to the thickness of the lens and assembling eyeglasses.
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