barcode scanner code in asp.net FIGURE 38.8 Approximate pin displacement as a function of pin length. in Software

Painting QR Code JIS X 0510 in Software FIGURE 38.8 Approximate pin displacement as a function of pin length.

FIGURE 38.8 Approximate pin displacement as a function of pin length.
QR Code ISO/IEC18004 Recognizer In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Maker In None
Using Barcode encoder for Software Control to generate, create QR image in Software applications.
38.3.3.3 Pin Binding and Friction in Grid Fixtures. As noted, the grid fixture pins must lean some distance to connect the grid to the on-product target location.Thus, the relationship between the plate thickness, hole diameter, and angle of displacement is critical. If the plates
Reading Denso QR Bar Code In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
QR Code Generator In C#
Using Barcode creation for VS .NET Control to generate, create Quick Response Code image in VS .NET applications.
PRINTED CIRCUITS HANDBOOK
Denso QR Bar Code Drawer In .NET
Using Barcode creator for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
QR Code Creation In Visual Studio .NET
Using Barcode creator for VS .NET Control to generate, create QR Code ISO/IEC18004 image in .NET framework applications.
FIGURE 38.9 Pin binding in multiplate tilt-pin fixture.
QR Code ISO/IEC18004 Encoder In Visual Basic .NET
Using Barcode printer for Visual Studio .NET Control to generate, create Quick Response Code image in .NET framework applications.
Bar Code Printer In None
Using Barcode creation for Software Control to generate, create bar code image in Software applications.
capture the pin too tightly, binding and friction can result. A pin that is held down below other pins in the fixture by binding will fail to make contact with the product (see Fig. 38.9). The spring force of the spring probe in the universal grid is intended to supply the pressure that presses the tilt pin against the product. Every bit of friction in the tilt-pin motion subtracts some of this force. If the friction is great, not only may the pin fail to contact, but if the pin is stuck high (toward the product surface), the product may press on it with undue force in shoving it back into the fixture, resulting in excess product marking. Binding can be caused within a single plate by hole diameters that are too small for the degree of pin tilt. Binding can result between plates if the plates are offset from one another, forcing the pin to bend as it snakes its way through the various plates. Binding can also result if the plate spacing is incorrect as compared to the design values. 38.3.3.4 Calculations for Tilt-Pin Fixtures. Modern fixture construction software should perform all of the necessary calculations automatically. Yet it is valuable to understand the basic decision processes. 38.3.3.4.1 Minimum Hole Diameter Calculation. The relationships between pin displacement, pin diameter, plate thickness, and drilled hole diameters are trigonometric. We calculate Eq. 38.1: A = sin 1 (PD/PL) and HSmin = [SD/cos(A)] + [PT tan (A)] + HT where HSmin = minimum hole size in a particular fixture plate PT = fixture plate thickness SD = pin shaft diameter as it passes through the plate PL = overall pin length PD = horizontal displacement distance of the pin tail relative to the pin head location A = angle of pin tilt expressed as degrees from vertical. (i.e., a vertical pin has a tilt of 0 ) HT = minimum acceptable tolerance to ensure that the pin slides freely in the hole (38.1)
Paint Barcode In None
Using Barcode drawer for Software Control to generate, create barcode image in Software applications.
Draw Code 39 In None
Using Barcode generation for Software Control to generate, create Code 3 of 9 image in Software applications.
The first term in the equation derives from the effective increase in shaft diameter in the horizontal plane as the pin tilts (see Fig. 38.10). The second term derives from the horizontal
Data Matrix 2d Barcode Maker In None
Using Barcode generator for Software Control to generate, create Data Matrix image in Software applications.
Code128 Generator In None
Using Barcode creation for Software Control to generate, create Code 128C image in Software applications.
BARE BOARD TEST EQUIPMEMT
Paint Standard 2 Of 5 In None
Using Barcode generation for Software Control to generate, create Standard 2 of 5 image in Software applications.
Barcode Printer In None
Using Barcode creation for Font Control to generate, create barcode image in Font applications.
FIGURE 38.10
Encode Code 128 Code Set C In VS .NET
Using Barcode drawer for Reporting Service Control to generate, create Code 128 Code Set B image in Reporting Service applications.
Code 128 Code Set C Creation In Objective-C
Using Barcode printer for iPhone Control to generate, create ANSI/AIM Code 128 image in iPhone applications.
Illustration of hole diameter calculations for a tilt-pin fixture.
Print EAN 128 In Visual Basic .NET
Using Barcode generator for Visual Studio .NET Control to generate, create UCC.EAN - 128 image in Visual Studio .NET applications.
Code 39 Full ASCII Generator In Visual C#.NET
Using Barcode encoder for .NET framework Control to generate, create Code 39 Extended image in .NET framework applications.
distance that the center line of the pin travels as it passes through the plate thickness. The third term, as mentioned earlier, is to provide a minimal clearance. For angles of tilt below 15 , the value of the cosine is close to 1 (over 0.96), and for rough calculations the term may be omitted. (For a 20 mil diameter pin, the contribution of pin tilt to effective shaft diameter is less than 0.7 mil). Similarly, for the same small angles, the calculation of the tangent can be simplified to tan(A) PD/PL. The error incurred increases as the plate thickness increases. For a 0.1 in. thick plate, the error at 15 will again amount to something less than a 1 mil hole diameter. With these simplifications, for low tilt angles and thin plates, the formula may be reduced to that shown in Eq. 38.2, with an extra mil or two added to the clearance. HSmin SD + [PT (PD/PL)] + HT (38.2)
Scan ANSI/AIM Code 39 In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
Bar Code Reader In .NET Framework
Using Barcode decoder for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
For the highest-accuracy applications, use the exact calculation. 38.3.3.4.2 Drill Bit Size Selection. Note that the minimum hole size calculated previously is often not the ideal drill size. The most common material used for grid fixtures is polycarbonate. Polycarbonate tends to have a finished hole size that is about 0.001 in. smaller than the drill size for plate thicknesses typically employed in fixtures. Therefore, 0.001 in. should be included in the tolerance figure HT to permit accurate drill bit selection. 38.3.3.4.3 Pin Lean and Pointing Accuracy. Pointing accuracy is defined as the pin s ability to hit an intended target, usually described as a radial dimension (the distance from the intended target to the actual contact location). Because the pin is typically not perfectly vertical, there are several possible sources of error, depending upon the type of pin employed.
Copyright © OnBarcode.com . All rights reserved.