Customizing standard products according to the customer's work site and workpiece geometry can further improve convenience. In this column, ESTIC would like to introduce the multi-spindle solution that supports synchronized tightening by combining two or more spindles of the nutrunner. This system can be easily introduced with simple customization to shorten work time, improve tightening accuracy, and achieve zero reaction force.

What is "Multi-Spindle"?

Multi-spindle is a customized solution that combines multiple nutrunners, enabling the simultaneous tightening of multiple screws. This allows for efficient and highly precise tightening. The nutrunner shapes vary, primarily featuring straight tools, and include a wide range of variations such as models with variable pitch functionality and swivel mechanisms.

The following image shows a simple 2-tool multi-spindle configuration, which combines two handheld nutrunners (straight tools) into a single unit. By gripping the trigger-equipped handles with both hands, you can tighten two screws simultaneously.

Multi-spindle has three key benefits: reduced work time, improved tightening accuracy, and zero reaction force.
Since multi-spindle can be implemented by making slight customizations to standard tools, it is cost-effective and easy to integrate. Despite its simplicity, it enables high-precision tightening of multiple screws, just like an automated system.

Here is the detail about the three key benefits of multi-spindle systems.

Three Key Benefits of Using Multi-Spindle

1.Reduced Work Time

Multi-spindle can tighten multiple screws simultaneously, significantly reducing work time. We cater to your needs for more efficient production.
For example, in cases where six screws are evenly arranged in a concentric pattern, such as on automotive tires, the standard process requires tightening six times. However, with a two-spindle multi-spindle system, the task can be completed in just three cycles, and with a three-spindle system, only two cycles are needed. Reducing the number of tightening cycles shortens the overall work time.

Multi-spindle is not only used for tires but also for circular automotive components such as crank pulleys and flywheels, where we have extensive successful implementations.
Additionally, multi-spindle supports diagonal synchronized tightening for square-shaped workpieces, ensuring balanced tightening at the four corners.
Furthermore, when tightening two rows of screws from the inside out, such as in engine cylinder heads, multi-spindle provide high-precision tightening, ensuring optimal tightening quality.

2.Improved Tightening Accuracy with Seating Synchronized Tightening

Why does tightening accuracy improve with multi-spindle?
When tightening multiple points on a workpiece one at a time, the workpiece may tilt, leading to uneven tightening.
Multi-spindle enables seating synchronized tightening, which ensures that all screws reach their seating position before final tightening begins. This function temporarily pauses screws that have seated first, allowing the others to catch up. Once all screws are seated, the system initiates final tightening simultaneously.
By tightening all points at the same time, the workpiece is evenly secured, significantly improving tightening accuracy.

The following video demonstrates the seating synchronous tightening motion of a multi-spindle (2 tools).

ESTIC's control units can be connected with just a single NET cable. When a tightening command is sent to a master control unit, the local units perform the same operation simultaneously. This function enables seating synchronous tightening.

3.Zero Reaction Force

Since reaction force generated during tightening is absorbed by the other tools, operator does not experience any reaction force, eliminating the need for a reaction arm. There are proven achievements of handling over 1000 N·m torque.

Customized Multi-Spindle Items

Multi-spindle can have variety of customized designs.

Multi-Spindle with Variable Pitch Function

It is useful when the distance between multiple screws varies or when tightening different models with different pitch requirements.

Some systems allow for manual pitch adjustment, while others incorporate electric actuators to enable automatic pitch variation.

Multi-Spindle with Swivel Mechanism

This multi-spindle features a handle-operated swivel mechanism, making it effective for horizontal tightening.

Compatible with Various Tool Types

Multi-spindles are commonly built using straight tools, but there are also proven cases using pistol tools and angle tools. Pistol tools: Reduce overall height Angle tools: Designed for horizontal tightening. Customized to match workpieces and worksite conditions.

Number of Tool for Multi-Spindle can be more than 3

In this page we have introduced multi-spindle solutions, using handheld nutrunners that can be easily implemented. ESTIC actually manufactures automated assembly systems with multi-tool configurations that perform full-axis synchronized tightening.
Since these systems are built from scratch based on customer requirements, they require a longer production period and higher cost. However, such machines offer exceptionally high tightening precision and reduced time required for tightening.

Others

In addition to the examples introduced in this page, we have a proven track record of manufacturing various multi-spindle systems.

Please feel free to contact us

ESTIC offers a wide range of standard line-up and extensive customized experiences to provide the optimal tightening solution for our customers.
Please let us know the tightening locations, workpieces, tightening torque requirements, and any challenges you are facing in the tightening process. We can also arrange preliminary demonstrations and conduct tests using your workpieces.

Please feel free to contact us first!