UPTOWER SOLUTIONS

Bolt Removal & Thread Repair

Fast and reliable up-tower repair of defective bolts and damaged threaded holes restore wind turbine performance and reduce downtime.

Broken bolts in structural connections and between main components are critical for the safe operation and structural integrity of the wind turbine. Band any resulting damage to the threaded holesneed precise repair to function reliably and above all secure safe operation and structural integrity of the turbine. Bolts can get stuck (impossible to untighten) or brake for several reasons. Using our mobile precision tools we are able to remove basically all defective bolts, fast, precisely and efficiently.

We can also restore threads that may have become damaged by the broken bolt. Depending on the damage in each case, our experienced technicians and diverse equipment allow us several thread repair options.

We can drill a larger hole around the original thread and cut a new thread, or mount a helical insert. Alternatively, we can use depth to drill deeper and cut a new thread. In either case, we are able to achieve the same strength as the original thread.. Repairing a damaged thread is not just about drilling a hole and cutting a new thread. To ensure the integrity of the joint it is equally important to ensure the correct position and angle of the repaired hole and thread. Here our customers benefit from our long experience and specialized equipment. We can remove and restore all bolt/thread dimensions

REDUCED DOWNTIME

Fast and efficient repair of bolts and threads onsite means that we keep the downtime of your wind turbine to a minimum.

IMPROVING PERFORMANCE

We can restore the performance and strength of threaded holes and its bolts

RELIABLE REPAIR

The bolts and threaded holes will operate safely and reliably after our repairs.

FLEXIBLE SOLUTION

We can remove all bolt dimensions and repair all threaded holes dimensions – from the smallest to the largest.

CONTACT US

Our team of experienced professionals will guide and advice you towards
the best possible solution that takes time, economy and durability into consideration.

Søren Kellenberger

Sales Director

+45 25 53 76 50 | ssk@cnconsite.dk

Process

From challenge to solution

Quotation request

Implementation

Handover

Follow-up

Quotation request

The wind turbine maintenance technicians contact us to report that a bolt, often including threaded hole, requires repair.

Our team responds within the same day and the repair job is discussed with the customer.

Based on the discussion with the customer a quote will be submitted.

The customer agrees to the proposal and the repair of bolts and threaded holess can start almost immediately.

Implementation

On-site repair of a wind turbine component.

Our technicians usually start work in the morning, transporting the equipment to the specific location in the tower or nacelle.

The team removes the broken bolt and repairs the damaged thread

Handover

Successful repair of a broken bolt on a wind turbine.

The customer can immediately install a new bolt and tighten it.

Based on the agreement we will submit a report for the repair works.

Follow-up

We offer customers a discussion with the technician who will carry out the next inspection.

Our follow up program complies with our high quality standards.

REDUCING DOWNTIME

„Depending on the type of turbine, it costs around 200,000 kr. per day when a wind turbine is inoperative. Sometimes more, sometimes less. We can create solutions that streamline the time consumption in each turbine and thereby reduce downtime. It’s economically beneficial for our customers‟

Aage Dam, CEO

Bolt Removal & Thread Repair

Learn more about bolt removal & thread repair in the Q&A section here:

Can broken bolts band damaged threads be repaired? Bolts can brake due to several reasons. Often a broken bolt leaves a part in the thread which needs to be removed before a new bolt can be installed. Some bolts are difficult to access and remove but CNC Onsite has specialized equipment which allow us to remove all types of bolts. When a bolt brakes this sometimes damages the thread as well. These can also be repaired in most cases. Typically the threads are repaired by drilling the hole deeper and cutting new thread or by enlarging the hole and make a bigger thread (afterwards use a larger bolt) or by installing a helicoil (to use same bolt size).

How are the bolts in the rotor blade repaired? How are threaded bushings repaired? Broken blade bolts can be more difficult to remove as the bolt has to be extracted through the blade bearing. CNC Onsite has specialized equipment to extract broken bolts from the blade bushings. Minor damages to the thread in the bushing can be repaired up-tower but if the thread is severally damaged it require further measures to repair it.

A damaged bolt or defective threaded hole has been detected. What is the process to repair it? The customer, usually the wind wind park technicians, contacts CNC Onsite. CNC Onsite will contact you (often within the same day) to discuss the damage with you. Photographs of the damage often accompany the descriptions. CNC Onsite will assess the extent of the damage to plan course of action.. As soon as the customer agrees to the quote, the CNC Onsite team and wind turbine owner determine a date to repair the affected bolts and/or threaded holes.

How quickly can a technicians come to the wind farm/park to repair a bolt? CNC Onsite’s repair technicians can be on-site , within a few days. Once the customer has agreed to the job we are ready to move out. How long does it take to repair a broken bolt or a damaged threaded hole? The time it takes to remove a broken bolt and repair the damaged thread is very much depending on bolt dimension and location, but often the actual repair work is done within hours or a day. During the initial contact CNC Onsite will receive information about the specific bolt dimensions and location and based on this a quote including a timeline is submitted. To optimize the repair process CNC Onsite will as part of the planning for job, go through the preparations needed in the turbine, the actual repair work and the final verification test.

What does it cost to repair a a blade bolt or a threaded bushing? Each job is different. We make a budget for each project to give the customer full transparency.