Parts
This section explains the parts that can be used with the Part Feeding option.
You can register up to 32 parts per project.
KEY POINTS
Epson has created a system for evaluating whether your parts are compatible with this Part Feeding option at our authorized distributors. For details, please contact an authorized distributor.
Conditions for Usable Parts
Parts that can be used with the feeder are subject to the conditions indicated below.
Vision System Compatibility
It is necessary that parts can be correctly identified by the vision system.
- It may not be possible to identify the shape of parts made of transparent plastic because light passes through them. Such cases can possibly be resolved by changing the lighting to outside the visible spectrum or by using reflected lighting.
- It might not be possible to identify parts by front/back due to their shape. Such cases can possibly be resolved by adding reflected lighting.
Size and Weight
Larger part size reduces the quantity of parts that fit on the platform (when spread out across the platform with no overlapping). If this quantity is small, the number of feeder operations increases resulting in a relative reduction of the robot operating time, thereby negatively affecting cycle time. The ideal quantity of parts is 50 pieces or more to be loaded to the feeder.
The gross weight of parts (Weight of one part × Quantity of parts that can fit on the platform with no overlapping) must be less than the load capacity of the feeder. Exceeding this weight overloads the feeder, negatively affecting the ability to separate parts and the cycle time, as well as reducing the service life of the feeder.
For the feeder load capacity, refer to the corresponding feeder manual.
Materials and Characteristics of Parts
The following parts are not suited for the Part Feeding option.
- Parts made of flexible or light material
Examples: Paper and fibrous materials - Parts easily damaged or deformed by vibrations, parts that generate dust when rubbed
Examples: Parts made of hardened powder or that are painted - Parts that are sticky, parts that leak liquid
Example: Food products
Shapes of Parts, Other Considerations
It is difficult to pick spherical parts because they do not remain still in the feeder. In this particular case, an optional Anti-roll tray will be required.
Examples: Bearing ballsParts that easily become entangled are difficult to separate.
Examples: Coil SpringsIt may not be possible to identify front/back of parts with different cross-sectional shapes made of material that is not transparent by using transmitted light. The following are some examples of such parts.
It is not possible to sort parts that are shaped differently in cross-section.
It is possible to sort parts by front and back if their outlines are asymmetrical when viewed from above.The best part to use when picking up parts by use of a suction system is one that has the suction surface that is parallel to the feeder base where the suction pad can move straight downward when picking up the part, and that secures the surface area for the suction pad. The following are some examples of such parts.
Spherical objects
Parts that prevent the suction surface from being parallel to the feeder base.
Cases where the suction position is an uneven surfaceIf using a suction method for picking, it is best if the parts do not have any differences in their center of gravity. The following are some examples of such parts.
Parts that lack a sufficient suction surface
Parts that cannot ensure a smooth surface (if using suction for feeding parts)
Parts where light passes through from belowIf used in an assembly process, it is best to implement measures to prevent the part position from becoming misaligned after being picked up. One such measure is to create guide holes in the parts and place a pin on the end effector to maintain alignment. Another measure is to install an upward-facing fixed camera to align the part position after picking.
Examples of Parts
Some examples of parts that can be used with the Part Feeding option are shown below.
Parts No. 1 to 3 are appropriate for the IF-240. No. 4 and 5 are not appropriate for IF-240 because they are too large and heavy. No.6 and 7 are not appropriate for IF-240 or IF-380 or IF-530 because they are too small and light.
| No | Photo | Characteristic | Size [mm] | Weight [g] | Comment |
|---|---|---|---|---|---|
| 1 |  | Metal press part | 10 × 10× 0.2 | 0.088 | IF-240 is suitable |
| 2 |  | Metal press part | 11 × 5.5× 0.2 | 0.029 | IF-240 is suitable |
| 3 |  | Plastic part | 10 × 9× 2.1 | 0.127 | IF-240 is suitable |
| 4 |  | Nylon connector | 21 × 29.9× 21 | 7.1 | IF-380 is suitable |
| 5 |  | Long nut | 36 × 11× 9.5 | 14 | IF-380 or IF-530 are suitable |
| 6 |  | IC | 5 × 4.4× 1.5 | 0.082 | IF-80 is suitable |
| 7 |  | Metal Bush | ø4 × 1 | 0.102 | IF-80 is suitable |
Note that No. 1 and 2 cannot be identified front/back by use of backlight only.
No. 3 can be identified front/back by use of backlight only.
Relation Between the Quantity of Parts Loaded to the Feeder and the Quantity Detected by Image Processing
The relation between the quantity of parts loaded to the feeder and the quantity detected by image processing is upward-convex shaped.
It is not possible to detect all parts in the feeder if the parts are such that they contact neighboring parts and overlap each other when loaded. The graph varies depending on how easily the parts contact neighboring ones or how easily they become overlapped. You can use the Part Feeding option to apply the optimal quantity of parts to load by use of calibration based on testing performed by Epson.
The graph shows the relation between the quantity of parts loaded to the feeder and the quantity detected by image processing for parts No. 1 and 3.
Be sure to pay attention to the facts that not all parts loaded to the feeder can be detected, and that the quantity detected changes depending on the quantity loaded.
Relation Between the Quantity Loaded into the Feeder and the Average UPM (Unit Per Minute)
The average quantity of parts picked up for a certain amount of time when performing pick-up operation is the average Units Per Minute (UPM). UPM is the number of parts handled by robot per minute.
The graph shows the relation between the quantity of parts loaded to the feeder and the average UPM for parts No. 1 and 3. Both the graphs for parts No. 1 and 3 are upward-convex shaped. Values for the vertical axis are not indicated because the average UPM varies depending on the robot speed, acceleration, and movement amount. In addition to robot operating conditions, it is important to keep in mind that the UPM changes depending on the quantity of parts loaded to the feeder and that there is an optimal quantity of parts to load to the feeder to increase the UPM.
Relation Between Feeder Operation and UPM (Unit Per Minute)
Time is plotted on the horizontal axis, and the operating devices are called "Robot", "Vision & Feeder", and "Hopper". The timing of operations by each device (Robot, Vision & Feeder, and Hopper) is plotted in the figure below. When operation starts, Vision & Feeder operation detect there are no parts in the feeder, resulting in the hopper being moved to load parts to the feeder.
After this, the feeder operates, parts are separated, detection is performed by the vision system, and the robot then picks up the parts. When all parts that can be picked up are gone, parts are once again separated and detected by Vision & Feeder operation. After that, the robot operates again.
The quantity of parts in the feeder decreases as Vision & Feeder operation and Robot operation are repeated. The hopper is operated to feed parts according to the timing for hopper operation corresponding to the specified threshold value. The graph presupposes parallel feeding operation.
UPM is zero (= 0) during Vision & Feeder operation because Vision & Feeder operation and Robot operation are repeated. The UPM while the robot is operating is a value larger than the average UPM indicated in "Relation Between the Quantity Loaded into the Feeder and the Average UPM (Unit Per Minute)". Note that the average UPM is the hourly average of the momentary UPM (= 0) while the Vision & Feeder are operating and the momentary UPM while the robot is operating.
Also note that the length of the blue lines of Robot operation in the figure are not uniform. This is because the quantity of parts that can be picked up differs depending on the separation status of parts in the feeder and because repeating pick-up operation reduces the quantity of parts in the feeder and the parts that can be picked up.
It is necessary to maintain a uniform quantity of parts in the feeder in order to stably perform part feeding.
Relation Between the Quantity of Parts in the Feeder and Hopper Operation
For stable part feeding, the graph below shows the momentary UPM (Unit Per Minute) and quantity of parts in the feeder at each feeder operation when performing run-out feeding from the hopper and when performing parallel feeding of an optimal 180 parts with 90 parts loaded in the hopper.
In run-out feeding, parts are not loaded from the hopper until the parts run out, resulting in the momentary UPM gradually decreasing, and when there are no more parts, parts are then supplied from the hopper and the momentary UPM returns to the original value.
In parallel feeding, the hopper operates when the feeder operates two to four times, and this reduces variations in the momentary UPM as the quantity of parts in the feeder does not drop below the lower limit.