IPC9850_Surface Mount Equipment Characterization.pdf - 第11页
IPC-9850 Official Proposal May 2001 11 For this standard, this refers to the number of nozzle utilized by the heads/spindles during the performance evaluation. 3.3.1.7 Number of Panels Built For this standard, this refer…
IPC-9850
Official Proposal
May 2001
10
The glass slugs are specified in Section 6.3. Due to the high quantity and packaging issues of discrete components,
placement test methods utilize production quality SOIC-16 and 1608C components that are specified in Section 6.5.
3.2.1.2 Machine’s Component Accommodation While the standard PVP is designed to accept a variety of
component types, placement patterns are prescribed only for a single type of component per PVP. This is done to
avoid a situation where certain machines are not capable of placing all of the specified components. Specific
examples include high-speed placement machines that are not designed to place QFP or BGA components and fine-
pitch machines that are not designed to rapidly place 1608C components. See Appendix E for the placement
locations to be used for each component type.
Each supplier may apply placement optimization procedures to the order by which components are placed, which
nozzle places a specific component, and which camera is utilized. However, it is expected that all spindles/ nozzles
shall be utilized as equally as possible, and that within the placements made by a particular spindle /nozzle, all
nozzle & rotation combinations shall be used as equally as possible (e.g. no manual manipulation to optimize the
pattern to exclude certain nozzles is permitted). At the very minimum, the population of the panel only requires the
use of one head and camera combination. The user has the responsibility to determine whether single or multiple
head and camera combinations optimize the balance between speed and accuracy results for a model type.
3.2.1.3 Panel-to-Panel Variability To captures both “within board” and “between boards” sources of variability for
each component, four-PVP are populated. The four panels are utilized to capture panel-to-panel placement
variation due to the fiducial finding process. The fiducial finding process accounts for imaging system errors in
reading the fiducials, mathematical analysis in accounting for panel orientation, etc.
3.3 Machine Performance Parameters
3.3.1 Test Conditions The Test Condition parameters section of IPC-9850-F1 report the machine conditions during
the execution of the speed and repeatability/ accuracy procedures. These conditions are selected to provide sufficient
information for a user to interpret and reproduce the documented performance.
3.3.1.1 Number of Heads/Spindles For this standard, this is the number of heads/spindles utilized by the machine
during the evaluation of performance. Each head/spindle should be used approximately equally. The placement
program is not to be manually optimized to avoid certain spindles or rotations. (A spindle moves up and down to
pick and place components. Nozzles are attached to the end of spindles and adapt spindles to a particular range of
component types. Some machines have multiple nozzle spindles. Some machines have multiple spindle heads. Other
machines have multiple heads.) Report the total number of heads/spindles used.
3.3.1.2 Type of Heads/Spindles This refers to kind of heads/spindles used to align the components. (Some
machines use one kind of head/spindle for fine pitch components and another kind for other components.) Report
the type of heads/spindles used.
3.3.1.3 Type of Camera
For this standard, this refers to the kind of camera used to align the components. (Some machines use one kind of
camera for fine pitch components and another kind for other components. Others are capable of aligning a particular
component type with more than one kind of camera.)
3.3.1.4 Number of Feeders/Trays
For this standard, this refers to the number of component feeders or matrix trays utilized by the machine during the
performance evaluation. (The number of feeders used affects the speed of some types of machines. Sometimes
multiple feeders per part number are required to maximize the throughput.)
3.3.1.5 Type of Nozzles
For this standard, this refers to the type of nozzle utilized by the spindles during the performance evaluation. (Some
machines may use more than one type of nozzle to pick and place a particular component type.)
3.3.1.6 Number of Nozzles
IPC-9850
Official Proposal
May 2001
11
For this standard, this refers to the number of nozzle utilized by the heads/spindles during the performance
evaluation.
3.3.1.7 Number of Panels Built
For this standard, this refers to the number of panel populated during the evaluation of performance parameters.
Calculation Method - The number of panels is specified in the procedure to be four.
3.3.1.8 Number of Parts Per Panel
For this standard, this refers to the number of components placed on each panel during the evaluation Performance
parameters.
Calculation Method - The number of component placed on each panel is specified by the placement program
corresponding to the specific part type.
3.3.2 Time-Based Parameters
These parameters describe the defined time periods that a board endures during a complete cycle of placing
components on a PWB (glass verification panel in this instance). Figures 3-1 and 3-2 show how these parameters are
defined.
Panel
Transfer
into
Work
Area
Fiducial
Read
Clamping Nozzle
Exchange
Total
Tact
Time
Unclamping
Panel
Transfer
Out of
Work
Area
Movement into
Buffer Zone
Movement
Out of
Buffer Zone
A Single Panel Cycle
Transfer Time Transfer TimeBuild Time
First
placement
Last placement
Figure 3-1: Performance Parameter Description for a Single Panel
A Four Panel Cycle
BuildTime
Total Tact Time
Transfer Time
BuildTime
Total Tact Time
Transfer Time
BuildTime
Total Tact Time
Transfer Time
BuildTime
Total Tact Time
Transfer Time
Panel #1Panel #2Panel #3Panel #4
IPC-9850
Official Proposal
May 2001
12
Figure 3-2: Performance Parameter Description for a Four-Panel Build
These measured parameters -- build time, transfer time and tact time -- must be obtained for the same panel
population build for which the repeatability and accuracy performance values are obtained.
The measurement procedures for these measured time-based parameters require the use of a stopwatch and/or an
oscilloscope. Stopwatches are utilized to measure the duration of a cycle. Oscilloscopes are usually utilized to
monitor hardware transitions in order to identify the start and end of a cycle for transitions that are not be easily (i.e.
repeatable and/or accurately) detectable with the naked eye.
The ability to measure a time-based parameter must be examined by the user to assure that measurements are
precise, i.e. both repeatability and accuracy are acceptable. The stopwatch and/or oscilloscope must have resolution
of at least 0.01 second or better. A GR&R study must be performed to verify that the repeatability of the
measurement is less than 0.01 seconds at a precision/tolerance ratio of better than 25% (see GR&R Discussion
Appendix G)
3.3.2.1 Build Time
Build time for this standard is the average time required to assemble each standard panel. It includes the time
required to align the panels as well as the time to place the components and change nozzles. Build time excludes the
time required to transfer the board into and out of the workstation. Some machines overlap the fiducial alignment
operation with the placement operation. Other machines overlap nozzle changing and pickups with the transfer
operation. The build time ignores these factors.
Measurement Procedure - Use a oscilloscope or stopwatch to measure the amount of time a panel is in the work-
area. Start the timing cycle when the clamp closes. Stop the timing cycle when the clamp opens. Populate four
panels and average the four measurements to obtain the build time.
Calculation Method - Build four panels and average the four measurements to compute the value of the build time
metric.
3.3.2.2 Transfer Time (T
t
)
Transfer time for this standard includes the time required to move the board into the workstation, clamp the board,
release the board and move the board out of the workstation. It represents the overhead associated with transporting
the board when production is flowing normally.
Measurement Procedure - Use a oscilloscope or stopwatch to measure the time from the entry of the first panel to
entry of the fifth panel (not required to be a verification glass verification panel), less the entire Build Time of the
four panels. To minimize measurement error, some easily detectable and clearly defined point in the cycle should be
utilized. Machines that buffer PWB's pre and post population may utilize additional panels to obtain a sustainable
pulse rate, but only the set of four consecutive glass verification panels is acceptable for a proper characterization
procedure.
Calculation Method - Take the time from the entry of the first panel to entry of the fifth panel (not required to be a
verification glass verification panel) minus the entire build time of the four panels divided by four to compute the
transfer time.
3.3.2.3 Total Tact Time
For this standard, Total Tact Time is the required time to place all components on verification glass verification
panels while maintaining the specified placement process capability. It excludes transfer time, fiducial time and
nozzle change time.
Measurement Procedure – Start the oscilloscope or stopwatch to measure the time at which the first component is
placed, and stop the oscilloscope or stopwatch at the time the last component is placed for each of the four panels.
3.3.2.4 Tact Time