Bosch Rexroth, the industrial division of the Bosch Group is collaborating with Maserati to develop the MC20 Industrie 4.0 production line at Maserati’s historic headquarters in Modena, Italy. The MC20 car is the first in the world with 100% of its screws electronically monitored by the Bosch Rexroth NEXO wireless screwdriver. Daniele Crespi, Product manager NEXO at Bosch Rexroth Italy answered a few questions.
What are the main advantages of the NEXO screwdriver? Better quality control? More flexible production? Zero defects?
Daniele Crespi: “The NEXO screw gun allows better quality control because it is able to monitor the entire tightening process across the entire line. The NEXO screwdriver is defined as an electronic multistep i.e. everything is electronically controlled and this means zero defects for the production.
The NEXO allows a flexible production because you have no cables and constraints, being WIFI and you can move around the piece to be screwed, you can use it without problems in hard-to-reach screwing points. Its ergonomic design guarantees maximum freedom of movement.
It also allows the highest configurability by reading the barcode with the production recipe, the NEXO set up immediately the job.”
How many types of clamping forces are recorded and where are these data recorded?
Daniele Crespi: “In a 4.0 production line, to control and monitor the production results is mandatory to send and collect the data to a server/cloud. This means that NEXO send clamping forces and screw results in real time during the production.
The internal memory of each NEXO can store up to 5.000 tightening data and relative curves. The goal is to work and send real time data once the job is finished. If there is a problem with the server connection, the NEXO can save the data and send it once the connection has been restored.”
Can NEXO automatically detect which type of clamping is required for which type of bolt without any operator intervention, just by reading the bar code of the part?
Daniele Crespi: “Yes. The NEXO sets up immediately after reading the barcode and selected the job related to the product.”
Does an operator have to supervise the tasks or is it monitored remotely?
Daniele Crespi: “All the critical screws, i.e. safety category (A) are remotely supervised by means of a guided conduct.”
Apart from the torque data, what other data can the screw gun retrieve?
Daniele Crespi: “The NEXO screw gun can read these data: torque and angle, timing and tightening curve.”
Can the screw gun detect the absence of a bolt and what does it do then?
Daniele Crespi: “Yes, the screw gun can detect the absence of a bolt. It can also check for any seizures (if this happens, the screw gun will stop to work) through the antigrip control.
The screwdriver can identify the correct nut, the feed torque – “run down” -, or if there is more or less friction (elastic tightening) and many other functionalities.”
If there is a fault, what does the screw gun do and what data comes back?
Daniele Crespi: “In a production fault, the screwdriver verifies the situation at each programming step. At each step it verifies the reached goal through the tolerance requested.
In a screw gun fault, the screw driver gives a “not ok” alert and the operator should follow the production instructions: do the job again or discard the product.”
The screw gun is an object connected to the wifi: in case of a communication failure, what does the screw gun do, what data goes up and where?
Daniele Crespi: “The operator can continue the job by selecting the manual setting through the barcode. This means that even if the connection falls down the production can continue. The screw gun can store the data in its internal memory (up to 5.000 codes) and the nit can send the data once the connection has been restored.”
Is this electronic clamping capability a regulatory requirement in the automotive industry? Are there, for example, many cases of car recall due to incorrect tightening ?
Daniele Crespi: “Yes, in automotive industry there are different requirements depending on the category of tightening. Each screw function has a different protection class: from severe personal injury to minor damage to the car. The goal is to minimize recall campaigns, maintaining the production line more flexible.
NEXO can for example also reduce the space on a working station. The screw driver can do up to 256 different programs with the same tool. This means less tool and screw guns in the plant and in the working stations, reduce the space and reduce the errors for an increased lean production level.”
What are the next steps? An autonomous screw gun ?
Daniele Crespi: “Depending on the production target, there are different processes that have to be implemented, automatically or manually. That’s why screw guns equipped on a robot or on an intelligent station already exist.
The R&D of these products is focused on getting the screw drivers more intelligent, performing, and ergonomic.”
Is Maserati the first Italian car manufacturer that you have equipped?
Daniele Crespi: “We supply automation solutions to the main important automotive Italian brands.”
How many screw guns are deployed on the Maserati line?
Daniele Crespi: “Maserati MC20 production line is equipped with 63 working stations with NEXO screw gun, 8 in the engine line and 55 in the assembly line. In some working stations, more than one NEXO is present.”