DE9016569U1 - Tape feeder for feeding tape-fed SMD components for SMD pick & place machines - Google Patents

Description

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ELECTRONICS

- Description -

Applicant: Fritsch Company Reference number

Gewerbestr. 37 G 90 16 569.1

7590 Achern 14

Tape feeder for feeding belted SMP components for SMD pick & place machines

For the SMD pick & place machine we developed, we spent a long time looking for a system available on the market for feeding belted SMD components. Unfortunately, we could not find a product that met our requirements in terms of the width of the feeder, ease of control and simple construction.

- State of the art -

Various types of tape feeders are available as feeding devices for taped SMD components for pick & place machines.

- Tape feeder with electronic drive. The belt with the components is transported from grid to grid by an electric motor. These feeders are controlled by an electrical signal or a light barrier

4 March 1991 Page Fa. Fritsch Elektronik, Gewerbestr. 37 759 Achern-Önsbach

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which is installed exactly above the removal point of the SMD components. The number of grid steps is adjusted to the size of the SMD components using a switch installed on the tape feeder, or simply using the number of electrical signals. The disadvantage of this tape feeder is its high price, which is particularly significant for SMD pick & place machines with over 100 installation options for tape feeders. Another disadvantage is the large width of the tape feeder due to the electric motor. If the tape feeder is to be controlled using electrical signals, the pick & place machine must provide this control option.

Tape feeder with mechanical drive. The drive for the feeder is attached to the assembly head of the pick & place machine in the form of a pneumatic cylinder. While the assembly head removes the component from the feeder, the pneumatic cylinder presses on the mechanics of the tape feeder and moves it one step further. Adaptation to different SMD components is achieved by changing the number of movements of the pneumatic cylinder or by using tape feeders with different step sizes. With the first variant, the assembly head has to remain in the pick-up position for an unnecessarily long time, which reduces the assembly performance. With the second variant, different feeders have to be made available for different components. It must be checked in detail whether there is sufficient space on the assembly head of the SMD pick & place machine to attach the pneumatic cylinder. This is particularly the case if the pick & place machine has an optical measuring system attached to the assembly head.

4 March 1991 Page Fritsch Elektronik, Gewerbestr. 37 759 Achern-Önsbach

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Tape feeder with permanent drive. All tape feeders on one side of the pick & place machine are driven by two permanently rotating toothed rollers. However, movement of the feeder is prevented by a lock in the tape feeder. This locking of the tape feeder is possible by a slip clutch between the driving toothed rollers and the conveyor wheel in the tape feeder. The electronics installed on the tape feeder remove the lock for one or more grid steps by means of an optical pulse from a transmitter diode attached to the pick & place machine's assembly head. The number of steps is set by a switch on the tape feeder. The drive of this variant is expensive due to the toothed rollers required over the entire length of the machine and the electric drive motors. The replacement of individual feeders is limited by the toothed roller located above the tape feeders.

- Task -

The invention specified in claim 1 is based on the task of creating a feed unit for SMD components that must remain under 15mm in width and is simple and inexpensive to manufacture. The drive of the feeder must be absolutely simple and yet very reliable. The entire mechanics of the feeder feeding station on one side of the SMD pick & place machine must be replaceable as a complete unit.

The changes to pick & place machines that want to use these tape feeders should be as minimal as possible. The feeders should be able to feed different grid sizes. The reel for holding the adhesive film of the SMD feeder

4 March 1991 Page 3 Fritsch Elektronik, Gewerbestr. 37 759 Achern-Önsbach

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The tape should be installed in such a way that the assembly head can move over the tape feeder. The reel must therefore not protrude more than approx. 10 mm over the housing of the tape feeder.

- Advantages -

Due to the small width of the tape feeders, the invention reduces the maximum number of tape feeders that can be installed on the pick &

' Place machines. This makes it possible to assemble larger circuit boards with the same machines. To control the feeders, i.e. to trigger a grid step, only an infrared transmitter diode needs to be attached to the assembly head. No other preparations are necessary on the assembly head of the pick & place machine.

The complete holder of the tape feeder on one side of the machine is designed as a unit. It can be completely removed and replaced with a second one. This means that the magazines can be prepared for the next type of circuit board while the assembly process is running.
The tape feeder is driven pneumatically. For a complete

, unit that can consist of up to 50 feeders, only two pneumatic cylinders are required. Since compressed air is required at every pick & place machine, this is a very cheap drive.

The tape feeders are adjusted to different grid dimensions via a rotary switch that is mounted on the tape feeders.

4 March 1991 Page 4 Fritsch Elektronik, Gewerbestr. 37 759 Achern-Önsbach

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ELECTRONICS

- Description of the invention -

An embodiment of the invention is explained using Figures 1 to 2 showing:

Fig. 1: The tape feeder as a single part

Fig. 2: The complete unit with transmitter diode on the placement head, the tape feeder with receiver diode, the busbars and the bracket with pneumatic cylinders and lifting beam.

In Fig. 1, the tape feeder is shown as a single part. The power supply and discharge lines are attached to the front of the tape feeder (1,1). The receiver diode (1,2) is located on the top front. The full SMD belts (1,13) are attached to the rear lower end. As soon as the receiver diode receives a signal from the transmitter diode (2,1) attached to the assembly head, the electronics (1,5) attached to the tape feeder start to work as follows:

- The lifting magnet (1,3) is connected to the voltage and is attracted. This pushes the lifting pendulum (1,4) forwards. At the same time, a pulse is sent to the output channel (1,1). This causes the central electronics (2,2) to move the lifting beam up and down once using the pneumatic cylinders (2,6). Since the lifting pendulum of the tape feeder is still pushed forwards by the attracted lifting magnet, the linear movement of the lifting pendulum can be converted into the circular movement of the tape feeder by the mechanism on the tape feeder. The lifting pendulum (1,4) is pushed upwards by the lifting beam (2,3), causing the conveyor lever (1,8) to rotate around its axis of rotation. The conveyor lever (1,4) tensions the grid conveyor (1,9) by one grid on the front side of the tape feeder. On the rear side, the adhesive film reel (1,10) is also pre-tensioned. Both pre-tensions are maintained by tension springs. During the return stroke of the lifting beam (2,3), both tension springs can be released again, whereby the gear wheel (1,12) and the adhesive film reel

4 March 1991 Page 5 Fritsch Elektronik, Gewerbestr. 37 759 Achern-Önsbach

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ELECTRONICS

roller (1,10) moves one grid further. This pulls the adhesive film from the SMD component tape during the forward stroke. The SMD component now lies open in the shell of the belt and can be picked up by the pipette (2,4) attached to the assembly head using negative pressure.

The number of conveyor steps is set using a rotary switch (1,6)(2,5) on the tape feeder. A button (1,7) is mounted on the tape feeder for manual conveyor of the tape. Pressing this button has the same effect as described above, with the difference that conveyors only advance one step at a time. This allows the operating personnel to influence the loading process.

Fig. 2 shows the complete unit consisting of an example tape feeder, the power rails and the lifting beam. The feeder can be inserted anywhere in the device. It rests on the front and rear rails (2,6)(2,7). The lifting beam (2,3) bridges the entire free space and runs into the recess visible in the tape feeder during the lifting movement. This complete unit can be attached to the pick & place machines and changed using a locking mechanism.

4 March 1991 Page 6 Fritsch Elektronik, Gewerbestr. 37 759 Achern-Önsbach

Claims (1)

4fFresh ELECTRONICS - Protection claims - 1. Tape feeder for feeding belted SMD components when using a pick & place assembly machine consisting of the individual tape feeders (the actual component feed stations) and a mechanism for holding the tape feeder housing and for generating the conveying movement of the tape feeders, characterized, that the mechanism for driving the tape feeders consists of a simple rectangular steel, which generates the conveying movement of the tape feeders by means of two pneumatic cylinders attached to the ends, whereby the tape feeders selected for conveying are stimulated by a light pulse, causing the lifting movement of this lifting beam. At the same time, by attracting the lifting magnet on the tape feeder, it is enabled to absorb the lifting movement of the lifting beam. With all other tape feeders attached, the lifting movement of the lifting beam passes through empty, since with these the lifting magnet holds back the driving lever. 2. Tape feeder according to claim 1, characterized, that an electronic rotary switch mounted on the tape feeder after the tape feeder is activated by a pulse from the transmitter diode mounted on the assembly head, transmits exactly the number of pulses that were set on the rotary switch to the central control. The central electronics in turn control the lifting movement of the lifting beam. 4 March 1991 Page Fa. Fritsch Elektronik, Gewerbestr. 37 759 Achern-Önsbach