In high-precision assembly scenarios such as engine cylinder heads and transmission housings, it's common to see this scene: after an intelligent electric screwdriver tightens a screw to the target torque, it doesn't immediately withdraw. Instead, it holds that state for a few seconds. This seemingly "redundant" action is actually a critical factor in determining whether the screw connection is qualified. It is precisely the "zero-speed hold" technique designed to address the "elastic aftereffect" characteristic of metals. Through in-depth optimization of this technique, Danikor intelligent electric screwdrivers provide a stable and reliable solution for demanding assembly applications.

When subjected to force, metal materials exhibit a dual characteristic of "instantaneous deformation + delayed deformation," a phenomenon known as "elastic aftereffect." During the screw tightening process, the moment the electric screwdriver reaches the target torque, the metal contact surface between the workpiece and the screw undergoes elastic deformation. However, this deformation is not yet fully stable at that point: if the tightening force from the screwdriver is removed immediately, the metal will slowly recover part of the deformation, resulting in the actual preload on the screw being lower than the design value.

This deviation may not have a significant impact in ordinary assembly, but it poses high risks in critical applications like engine cylinder heads. If insufficient preload due to elastic aftereffect leads to oil leakage, cylinder pressure drop, or in severe cases, engine seizure. Traditional tightening processes often resort to "over-tightening compensation" to deal with this, which ironically increases the risk of thread stripping.

The essence of zero-speed hold technology is to provide a "stabilization time" for metal elastic deformation, eliminating deviation through three key steps:

1. Do not withdraw when torque is reached: When the electric screwdriver reaches the target torque, it does not stop the power output immediately. Instead, it maintains the current torque value with a rotational speed of 0 (i.e., "zero speed").

2. Wait for deformation to stabilize: During the hold state, the metal deformation between the workpiece and the screw gradually transitions from "unstable" to "stable," and the preload force also approaches the design value.

3. Withdraw after confirmation: After the preset hold time, once the system confirms that the preload is stable, it controls the electric screwdriver to withdraw, completing the entire tightening process.

Throughout this process, the electric screwdriver must possess dual capabilities of "real-time torque monitoring + zero-speed control." Ordinary electric screwdrivers, unable to stably maintain torque, find it difficult to implement this technique.

Danikor intelligent electric screwdrivers have made the following key optimizations for zero-speed hold technology, making them suitable for demanding applications like engine cylinder heads:

1. Torque compensation: During the hold process, if the torque drops slightly due to deformation, the system will output compensating torque in real time, ensuring that the torque remains stable within the target range throughout the process, avoiding preload force fluctuations caused by torque variations.

2. Customizable parameters: Supports autonomous setting of hold time based on workpiece material (such as aluminum alloy cylinder heads, cast iron cylinder blocks) and screw specifications, meeting personalized needs of different scenarios.

3. Visual traceability: Records torque curves and time data during the zero-speed hold process through supporting software, allowing intuitive viewing of the deformation stabilization process. It also supports integration with MES systems, enabling full-process traceability of tightening quality.

As precision manufacturing continues to raise the bar for assembly quality, zero-speed hold technology has evolved from an "optional feature" to a "mandatory configuration." Brands like Danikor, through technological optimization, make this function more aligned with practical needs, providing reliable assurance for tightening quality in critical fields such as engines and new energy batteries.