Automated Screw Tightening Robot Examples of In-House Production
Real examples from Oriental Motor production facilities of screw tightening equipment used to explain points for adoption of products.
In addition, Oriental Motor provides services to support equipment design. Please feel free to contact Oriental Motor if you have any questions.
Real Example of Equipment Screw Tightening Equipment
Equipment Overview
This a screw tightening equipment consisting of a cartesian robot (gantry unit) and a screw tightening axis.
The cartesian robot (gantry unit) moves to match the position of the 4 screws, and the AZ Series motor tightens them.
This equipment has made it possible to automate screw tightening, which used to be done manually, and has contributed to making the equipment size more compact, reducing the burden on workers, and leveling out work hours.
| Number of Axes | 4 axes |
|---|---|
| Cycle Time | 23.0 s (4-point screw tightening) |
| Stroke | Axis 1 (x) 125 mm/s |
| Axis 2 (y) 250 mm/s | |
| Axis 3 (z) 50 mm/s | |
| Axis 4 (screw tightening) 420 r/min | |
| Screw Tightening Possible Range | W200 mm×D150 mm×H50 mm |
| Main Power Supply | 100 VAC* |
* The power supply for driving and controlling the driver is 24 VDC.
Cartesian Robots (Gantry units)
| Product stroke | Maximum speed | Repetitive Positioning Accuracy | |
|---|---|---|---|
| Axis 1 (x) | 200 mm | 230 mm/s | ±0.02 mm |
| Axis 2 (y) | 250 mm | 400 mm/s | ±0.02 mm |
| Axis 3 (z) | 50 mm | 280 mm/s | ±0.02 mm |
Screw Tightening Axis
| Maximum Screw Tightening Torque | 0.77 N·m |
|---|
Interview with an In-House Equipment Designer: Key Points of Cartesian Robots (Gantry units) for Screw Tightening Equipment
Achieves automated screw tightening with minimal required installation area and no interruption of line flow
In order to automate the screw tightening process, there were design issues such as "the size of the equipment is too large relative to the load for commercial products" and "we want to lower the cost." Oriental Motor has solved this problem by producing cartesian robots (gantry units) in-house.
【Background on Selection of the Cartesian Robot (Gantry Unit)】
- By using an electric actuator with a stroke that matches the load, screw tightening can be automated in a minimum amount of space
- Main axis side (XYZ axis) moves, enabling a production line that does not stop the flow
Features of gate-type with moving table [top view]
| Required Installation Area: | Wider than cartesian robots (gantry units) Requires space for the table's range of motion regardless of load size |
|---|---|
| Flow of line: | 2 Processes Occur (① Conveyor → Table, ② Table → Conveyor) |
![Features of gate-type with moving table [top view]](/sites/default/files/image/solutions/casestudies/in-house-machine/05/in-house-machine-05_02.webp)
Features of the cartesian robot (gantry unit) [top view]
| Required Installation Area: | Narrower than gate-type Using an electric actuator with a stroke appropriate for the load enables space saving in the installation area |
|---|---|
| Flow of line: | Does not stop |
![Features of the cartesian robot (gantry unit) [top view]](/sites/default/files/image/solutions/casestudies/in-house-machine/05/in-house-machine-05_03.webp)
System Configuration
Each axis is controlled by EtherNet/IP.
Your own robot can be built easily with the AZ Series,
and robot controllers that can be configured and programmed are also available.
* The MRC01 is not used in this example of in-house production of equipment.
List of Components
| Product Name | ||
|---|---|---|
| Axis 1 | Electric Linear Slides | EASM6LXE020AZAC |
|
EtherNet/IP Compatible Drivers | AZD-AEP |
| Connection Cable | CC050VZF | |
| DC Power Supply Cable | CC02D010-3 | |
| Axis 2 | Electric Linear Slides | EASM4YE025AZAC |
|
EtherNet/IP Compatible Drivers | AZD-AEP |
| Flexible Connection Cable | CC050VZR | |
| DC Power Supply Cable | CC02D010-3 | |
| Axis 3 | Electric Cylinders | EACM4RE05AZMC |
|
EtherNet/IP Compatible Drivers | AZD-AEP |
| Flexible Connection Cable | CC050VZRB | |
| DC Power Supply Cable | CC02D010-3 | |
| Axis 4 | αSTEP | AZM48A1C |
|
EtherNet/IP Compatible Drivers | AZD-AEP |
| Flexible Connection Cable | CC050VZR | |
| DC Power Supply Cable | CC02D010-3 | |
- * EtherNet/IP™ is a trademark of ODVA.
- * All motor cables are 5 m in length.
- * All DC power supply cables are 3 m in length.
Axis 1, Axis 2
Electric Linear Slide EAS Series
Axis 3
Electric Cylinder EAC Series
Axis 4
αSTEP AZ Series
Axes①② Cartesian robots (Gantry unit [X- and Y-axes])
<High permissible moment> Electric Linear Slide EAS Series
High Rigidity Design Reduces Product Defects (Screw galling and position errors)
If the rigidity of the mechanism is low, it may not be able to withstand the reactive force of screw tightening and the entire mechanism may deflect. Deflection of the entire mechanism can cause defects such as galling or screw position errors.
The high rigidity EAS Series suppresses equipment deflection and contributes to the reduction of product defects.
For EAS6
Even when the overhang length is 1 m, a pressing force of up to 110 N is permissible.
Pushing force and load values are calculated from the static permissible moment of EAS6, 110.0 N·m. (The weight of the board is not taken into account.)
Permissible Moment Value
| Model | Static permissible moment*1 [N·m] | Dynamic permissible moment*2 [N·m] |
|---|---|---|
| EAS6 | MP: 86.0 MY: 34.0 MR: 110.0 |
MP: 31.8 MY: 10.3 MR: 40.6 |
| EAS4 | MP: 58.3 MY: 16.0 MR: 53.3 |
MP: 16.3 MY: 4.8 MR: 15.0 |
- *1 Load moment that the linear guide can support while the motor is stopped
- *2 Load moment that the linear guide can support while the motor is in operation
Motor fold-back specification makes the equipment compact overall
The use of a reversed motor type linear slide with a short overall length has achieved a compact design of the equipment. This allowed the linear slide to fit within the equipment width limitations of the line.
View of Cartesian Robot (Gantry Unit) from X-axis side
EAS4 electromagnetic brake type with 200 mm stroke
A Wide Variety of Strokes for Flexible Combinations
The EAS Series is available in a range of strokes from 50 mm~850 mm in 50 mm increments. X and Y axes can be combined as appropriate for the size of the load.
Related Products
Electric Linear Slides EZS Series
<Highly rigid design that helps reduce product defects (screw galling and misalignment)>
The motor section is equipped with the high efficiency, energy saving αSTEP
AR Series and AZ Series. 2 types of linear slide sections are available: straight type and reversed motor type. The simple dust-resistant structure made from a stainless steel sheet prevents ingress of foreign particles and reduces emission of dust.
Axis③ Cartesian robot (Gantry unit [Z-axis])
Electric Cylinder EAC Series
Reduces Overhang of Z-Axis and Screw Tightening Parts
The electric cylinder has a thinner structure than the electric linear slide, which can reduce the overhang.
In addition, use of a reversed motor type with a short overall length has achieved a compact design of the equipment.
Top view of screw tightening equipment
EAC4 electromagnetic brake type for 200 mm stroke
Press With Appropriate Force When Tightening Screws
The push-motion operation function, which allows for setting of the torque limiting value, pushes the screw with the appropriate force. The push force can be limited by setting the push current.
Maximum push force and push current upper limit value (reference value)
Built-in Products
Electric Cylinder EAC Series
The motor section is equipped with the high efficiency, energy saving αSTEP AR Series and AZ Series. 2 types of cylinder sections are available: straight type and reversed motor type. For push and carry applications, firstly choose from the EAC Series.
Axis④ Screw Tightener
αSTEP AZ Series
Limits the Generated Torque to Prevent Galling and Over-Tightening of Screws
The push-motion operation function, which allows for setting of the torque limiting value, prevents damage due to over-tightening. TLC output, which is the output when the torque limiting value is reached, andmonitoring function. Also,monitoring function can also be used to check for abnormalities such as "screw galling" and "screw position error" that can lead to product defects.
Introducing the Perfect Motor for Adjusting Torque and Tension
Built-in Products
Battery-Free Built-In Absolute Encoder αSTEP AZ Series
αSTEP, which employs Oriental Motor’s unique closed loop control, is equipped with a newly developed ABZO sensor.
Absolute systems are now possible with no battery required. A range of network compatible drivers is also available to achieve advanced positioning at an affordable price.
Common to All Axes
αSTEP AZ Series EtherNet/IP™ Compatible Driver
Controlling Motors from the Network
It can be controlled directly from the network. The connection between the host control device and an EtherNet/IP compatible driver is made using a single EtherNet/IP communication cable, cutting down on wiring.
Other products are also available for various industrial networks.
- EtherNet/IP™ is a trademark of ODVA.
EDS Files Available
EDS files are available to help you use EtherNet/IP compatible products more easily. EDS files can be downloaded from the related product details page.
αSTEP AZ Series
Detects Equipment Conditions and Screw Tightening Abnormalities That Result in Product Failure
The AZ Series can monitor motor position, load factor, and more. When the monitoring status of each item reaches a customizable setting value, a signal is output.
The monitoring function can detect equipment conditions and screw tightening abnormalities that can lead to product failure based on changes in position, torque, etc.
In addition, since it can monitor the accumulated rotation from the start of use, it contributes to the visualization of experience-based know-how, and to predictive maintenance.
Mechanical Absolute Encoder, No External Sensor or Battery Required
The AZ Series is equipped with a built-in battery-free mechanical absolute encoder <ABZO sensor>. Position information is retained even if the power supply is shut down due to an emergency stop or blackout or the cable between the motor and driver is disconnected during positioning operation.
In addition, since the home and software limit can be set using absolute position information, no external sensor is required.
Achieves Various Movements with Unified Control
αSTEP The AZ Series offers a product line of standard type motors in small sizes, as well as motors with electromagnetic brakes, gearheads, and more. Oriental Motor is also developing actuator products that combine motors and actuators. Wiring, control, and maintenance parts have been standardized, as the various motors, drivers, cables, etc. are common to the equipment, which reduces the time and effort required for start-up.
Built-in Products
αSTEP AZ Series EtherNet/IP™™-Compatible Driver
This driver is compatible with EtherNet/IP. As Oriental Motor AZ Series motors can be connected with electric actuators that carry these, they can be used for a wide range of applications.
Battery-Free Built-in Absolute Encoder αSTEP AZ Series
αSTEP, which employs Oriental Motor’s unique closed loop control, is equipped with a newly developed ABZO sensor.
Absolute systems are now possible with no battery required. A range of network compatible drivers is also available to achieve advanced positioning at an affordable price.
Support for Equipment Design from the Product Selection Stage
Support for Motor Selection
Oriental Motor also offers a service where our dedicated staff can select motors on customers’ behalf. Please refer to the link for details.
