Automower: Blades getting bent (or) Cutting assembly making a loud rattling sound.

Symptom: Automower makes loud noise when mowing AND/OR the blades of the Automower are bent, which is preventing the pivoting movement of the blades. A picture of bent blades is shown below as an example.

Cause: This issue is most likely caused due one of the following reasons,

1. A wobbly skid plate on the cutting blade assembly is causing the sound
2. Worn out blades that thin out and bend upon contact with hard objects can come in contact with the skid plate and create a rattling sound. Blades can even bend if the mower cutting blade assembly comes in contact with an hard object and the impact is on the blades.
3. There is a cutting disc imbalance - Caused when a blade is broken or missing (OR) There are more than 1 blade installed on one of the slots (the blades are sometimes stuck  together and while changing blades, it is easy to mistakenly install two blades in a single slot.)
4. The cutting assembly has dirt and/or object such as string, grass weed, hair or wire stuck in the motor.

Details & Resolution:

For causes #2, #3 and #4, the resolution is pretty simple. The blades need to be checked and changed if broken or double blades installed. The cutting assembly can be opened and any debris or external object can be easily cleaned. If unsure, drop the mower off at SmartDots and it will be taken care of.

For #2, the cutting blade assembly or its parts may need to changed. The cutting blade assembly consists of multiple parts that makes it possible for the Automower to execute the cutting functionality effectively. It is important that the cutting blade assembly is regularly inspected visually for physical damage, as it is most prone to external damage. It is also important that your mower is given for annual service and maintenance every year.

The different components of a cutting blade assembly are shown below,

The skid plate cover (Part #14) is responsible to securely hold the skid plate against the Cutting Disc. between the Cutting disc and Skid plate there is a narrow gap where the baldes are installed. If the Skid Plate is not secured properly (which can be caused due to poor threading on the skid plate cover or damaged cover), then the chances are that the skid plate will wobble inconsistently, applying vertical pressure on the blades as the disc rotates. This will cause the blades to press against the cutting assembly and start bending.

To resolve this issue, the skid plate cover should be checked and replaced if needed. The cutting blade disc should also be inspected for proper threading and grip. Depending on the Automower model, the best solution may also be to change the entire cutting blade assembly, even though other components may not look damaged. This is because, the wobbly skid plate could have damaged the bearing and other components that may not be clearly visible. Considering the relatively low cost of the cutting blade assembly, it may be feasible to change the entire cutting blade assembly for some of the Automower models like 315X.

If the cutting system does not look damaged and the blades are bent, then the issue may be resolved by simply changing the blades with new ones. 

If you notice bent blades on your Automower consistently within a few days of blade change, then it is likely that the cutting assembly needs to be changed. You can just send an e-mail to [e-mail] with pictures and detailed description and we will be glad to help. SmartDots will determine the next steps based on all the information available. Depending on the issue, you may also need to drop the mower off to SmartDots workshop for repair.