Nordson_EFD_RV_Series_Operating_Manual.pdf - 第23页

RV Series Automated Dispensing Systems 23 www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide. About Of fsets Offset is the distance between …

RV Series Automated Dispensing Systems

22 www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide.

Concepts

Before creating any programs, make sure you understand the concepts explained in this section.

About Programs and Commands

A program is a set of commands stored as a ﬁle. Each command is stored in the ﬁle as a numbered address.

Commands can be subdivided into the following command types:

• A setup command sets a program-level parameter, such as an XYZR coordinate or the Z clearance height.

• A dispense command is tied to an XYZR coordinate and automatically sends a signal to the dispensing system

to execute the dispense command.

When the robot executes a program, it steps through each address in sequence and executes the command

contained in that address. If an address contains a setup command, the system registers that command. If an

address contains a dispense command, the robot moves the X, Y, Z, and R axes to the location speciﬁed for that

command and then performs the dispense command.

Dispense commands are the building blocks of patterns. To program a dispense command, the dispensing tip is

jogged to the desired XYZR location and then a dispense command is registered for that location. This action is

repeated until the desired dispensing pattern is complete. Several examples are provided below.

Setup commands dictate how dispense commands will be executed. Nordson EFD recommends inserting setup

commands at the beginning of a program. The following setup commands are the most commonly used: Backtrack

Setup, Dispense Dot Setup, Dispense End Setup, Line Dispense Setup, Line Speed, and Z Clearance Setup.

Dispense Command Examples

Commands Resulting Pattern (Overhead View)

To program the robot to dispense a dot of ﬂuid, an

XYZR location is registered as a DISPENSE DOT

command.

DISPENSE DOT

To program the robot to dispense a bead of ﬂuid along

a linear path, the XYZR location of the start of the line

is registered as a LINE START command. The locations

where the tip changes direction are registered as LINE

PASSING commands. The location where the bead of

ﬂuid ends is registered as a LINE END command.

Line Start

Line EndLine Passing

Line Passing

To dispense a bead of ﬂuid in an arc, the XYZR location

of the start of the bead is registered as a LINE START

command. The high point of the arc is registered as an

ARC POINT command. The end of the arc is registered

as a LINE END command.

Arc Point

Line Start Line End

Lines and arcs can also be combined to dispense a

bead of ﬂuid along a complex path.

Line Start

Line End

Arc Point

Line Passing

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About Offsets

Offset is the distance between two components. The system must be “taught” the following offsets before any

programs are created:

• Camera-to-tip offset: the distance between the center of the camera view and the center of the dispensing tip

(this is an XY offset).

• Tip-to-workpiece offset: (1) the distance between the bottom of the tip and the workpiece for contact

applications or (2) the distance between the bottom of the nozzle and the workpiece for non-contact

applications (this is the Zclearance).

These offsets must be properly calibrated to make sure the dispensing tip follows the same path as the camera and

to compensate for slight variations in height that occur when a dispensing tip or nozzle is changed.

Offsets are taught to the robot during the setup and calibration process, which is guided by the Robot Initial Setup

wizard. This process must be performed for initial startup and also after any change to the system. Examples of

system changes include the following:

• Any time a component installed on the Zaxis (such as the syringe barrel or camera) is moved.

• Any time a dispensing tip or nozzle is changed.

About Programs and Commands (continued)

Best Practices for Programming

• Insert dispense setup commands at the beginning of the program.

• Insert mark commands before any dispense commands.

• Insert dispense commands after inserting setup and mark commands.

• Insert the End Program command at the end of all programs.

Illustration of camera-to-tip offset (also referred to as XY offset) and tip-to-workpiece offset (also referred to as tip height or

Zclearance)

Camera-to-tip

XY offset

Tip-to-workpiece

offset

(Z clearance)

Camera-to-tip

XY offset

Tip (nozzle)-to-

workpiece offset

(Z clearance)

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About Marks

To recognize that a workpiece is present or to determine its orientation on the ﬁxture plate, the system uses marks

and ﬁducial marks. Marks are reference images (pictures of a small area on a workpiece) taken by the camera and

stored in a location called the Mark Library. The Mark Library appears in the Secondary View screen when the

Camera tab is selected. The stored images are shown in sockets in the Mark Library. Picture sockets are blank if

they do not contain a stored image.

A mark is a single image that the system uses to ﬁnd a speciﬁc location on a workpiece. Fiducial marks are two

mark images that are used conjointly to (1) identify whether a workpiece is present in the proper XY location and (2)

to understand its angle of rotation, and then to make automatic adjustments to the program accordingly.

Picture socket with

a stored mark image

Blank picture

socket (no stored

image)

Location of mark image ﬁles on the DispenseMotion controller

Best Practices For Selecting a Mark Image

• The selection should be on the actual workpiece (not on the ﬁxture plate) because it is the workpiece position that

the system adjusts to.

• The selection should be unique. There should be only one selection of its kind within the camera view. For

example, don’t choose one of many small circles that are within the camera view.

• Sharp features are best. For example, the intersection of two lines in the capital letter T would be better for a mark

image than the center of a circle, which possesses no ﬁnite lines.

• An actual dispensing position, such as the corner of a silk-screened solder pad, is more effective than the broken

corner edge of a pallet of circuit boards because of the differences in their manufacturing precision.

• The further away ﬁducial marks are from each other, the more precise the system will be in locating them on a

workpiece.

Mark Image Files

You can store 240 mark images in the sockets available in the Mark Library. The Mark Library appears in the

Secondary View screen (refer to “Secondary View Screen” on page30 for more information). These marks are

stored as ﬁles on the DispenseMotion controller under D:\ever_sr\mark.

Camera screen shown in the Primary View screen and the Mark Library shown in the Secondary View screen

Mark Library