Measure the CMM scanning technology in modelling

The foreword flying development as car, shipping, aviation, spaceflight and mould industry, the demand that waits for a respect to product exterior, function is higher and higher, make free curved surface spare parts received wider and wider application in modern industry. And be in product and mould development process, the design often is not from foregone blueprint or theory data begins, however direct with objective appearance regard a design as basis or referenced model. Accordingly must have the aid of measures equipment at coordinate, get data from objective model, use measure modelling technology to get CAD maths model undertake in order to facilitate modification, generate numerical control code to produce a product or development to create a pattern through CNC at the same time. Because computer technology is making the wide application of the domain, digitlize the swift and violent progress that measures a technology especially, be based on the product model technology that measures data to become the main target that converse project technology pays close attention to. The article introduced to measure the three-dimensional scanning technology that uses in modelling, to its precision, speed, suitable scope undertook analysis and quite, with 16 the popular ultrathin CRT television on the market is at present medium: Awl of 9 compressed Bo and ZEISS VAST scanning measure a head to be exemple, the key introduced to be based on 3 coordinate to measure machine (CMM) the application of contact scanning technology in measuring modelling. 2.

Brief introduction of three-dimensional scanning technology is three-dimensional scanning is collect light, machine, report and computer technology the new and high technology at an organic whole, basically use at undertaking scanning to object space appearance and structure, in order to obtain the dimensional coordinate of object surface. Its principal port depends on the digital signal that can be the stereo information changeover of objective the computer to be able to be handled directly, for objective digitlization provided quite convenient and quick measure. Three-dimensional detect the technology is close will 10 years develop the burgeoning research field that rise flourishingly, common three-dimensional object form detects the method can be divided for contact and blame contact two kinds big, and the action of testing system and object nothing more than the means such as smooth, sound, machine, report, detect basically following plan institute show the method. Graph appearance of 1 three-dimensional object detects the watch below the method is opposite from precision, speed, suitable scope detect basically the method undertook analysis and quite. The comparison that expresses all sorts of measurement technique is not a contact to measure a digitlization rate is high, for instance laser takes scanning to be able to achieve 19000 a little bit, 3D is become resemble every can be being amounted to 1, 300, at 0 o'clock (one needs 10 seconds to plant about) , however, the precision that is not a contact to measure a head is lower, under 25 micron (100100x100 Mm3) , and object surface condition: Be like quality of a material, color surface roughness turns over smooth pitch to wait, metropolis influence blame contacts the digitlization effect that measures a head. In addition, existing optics is three-dimensional those who measure mainstream technology and its equipment to basically be aimed at is diffuse reflection object is three-dimensional measure, measure object of blame diffuse reflection effectively hard. And in applying actually, the exterior property of a large number of objects that be measured is blame diffuse reflection, be in especially industrial domain, be not diffuse reflection object is to have larger proportion more, wait for finish machining component, printed circuit like polishing mould board solder dot. For the finish machining workpiece in the application that to hoping high accuracy copies or production, use contact scanning measures a head to still have the advantage that cannot replace. Contact is measured in use at present most extensive with most reliable method it is coordinate is measured machine (CMM) . Traditional measurement chance is much use touch hairdo contact to measure a head, every time gets value of coordinate of the X of on free curved surface a bit, Y, Z. This kind measures speed slow, and the curved surface information that measures very hard more in the round. At the beginning of 90 time, a few coordinate survey engine production manufacturer, develop a three-dimensional force displacement to pass the scanning of feeling to measure a head early or late, these measure a head to be able to slide on workpiece measure, get coordinate information of the surface continuously, its scanning speed can be as high as 8m/min, digitlization speed can be as high as 500 to nod / second, digitlization precision can achieve 1 micron, defect is digitlization rate is low. But the 3 coordinate machine of German ZEISS passes his active imitate of VAST of high speed scanning measures head and powerful CALYPSO, HOLOS, DIMETSION to wait measure software to identify automatically from diagnostic element, maths searchs, scanning of sealed curve curved surface is waited a moment great rate land made up for the respect to measure efficiency issue, as three-dimensional as blame contact detect the pre-construction work with methodological more need if gush developer, stick reference point or referenced ball, adjust setting brightness or the photograph such as the data processing of bigger workload compares later period, in always cost on shortened difference, become high accuracy workpiece to seek metrical good alternative instead. 3.

Contact scanning mapping applies example to be in glasswork production, develop plan to accelerate a product, besides undertaking according to the product blueprint that the user provides the mould is designed, ask to be being used actually what sample objective undertakes mapping modelling can understand a product better and give mould antrum measure well and truly certainly quickly. To glass object of such blame diffuse reflection, contact scanning is measured the advantage that cannot replace is had in precision and career respect. Graph scanning of 2 sealed lines measures medium compressed Bo awl to pursue 3 measure result IGES to output a graph 2, 3 for the market is at present genteel 16 in the ultrathin CRT television of travel: Awl of 9 compressed Bo measures maths of the Iterative BaseAlignment in software is being measured with CALYPSO on machine to look for execute to build workpiece coordinate in ZEISS PRISMO is hind, the IGES that CAD module embeds to measure result and workpiece coordinate department to the curve inside the situation that measures a head to have contour line of the scanning that close a line with VAST scanning by mode of sealed curve Digitize and CALYPSO is outputted accurately. The need after measuring a law to obtain workpiece appearance to nod cloud data with blame contact passes the special RE software such as Surfacer, CopyCAD to undertake dividing a confusion of voices, filter, flowing, few and far between wait for pretreatment to differ, as a result of active the coordinate that successive scanning measures a head to be able to get accurately measuring a place and law arrow, so the job of data pretreatment greatly simple. To Bo awl the data that measure a place needs purify only two end hit every curve measure a few data near the dot and the individual and unusual drop when the curve is being built by dot compose in CAD software can. Software of graph 4 CAD measures result data mediumly to choose a plan the method that the dot data after modelling of 5 products CAD will be handled guides face of → of the line that nod → is pressed in CAD software one by one compose builds a curve, the method that has used a curve to make a range again separates a compose side, pass curved surface next the model that editorial method gets whole product. Or it is to pass the special RE software such as Surfacer, CopyCAD to undertake dividing a confusion of voices, filter, face of triangle of the flowing, construction after waiting for pretreatment thin piece second birth becomes curved surface the modelling of attainable also whole product. If pursue 4, 5 are shown. 4.

The last word undertakes to objective model medium three-dimensional data collects a means metrical molding process varied, blame contact or contact scanning are measured have respective applied range, in high accuracy and the measurement that are not diffuse reflection object to wait, be based on 3 coordinate to measure machine (CMM) contact scanning measures a head to still have clear advantage, will continue to produce main effect in product and mould development. CNC Milling CNC Machining