NAVCO was approached by a manufacturer of laser cut metal sheet parts looking for a safer, more efficient way of de-nesting the cut parts from the sheet. Their current solutions of shaking and dropping by hand and utilizing handheld knockers had become a safety concern and was bottlenecking production. Their laser cutter operators were bending over to lift, shake, and drop the sheets to dislodge the more easily removed parts, then would run a handheld knocker or hammer over the remaining parts to completely denest the sheet. They were looking for a solution that could be easily integrated within the current work envelope and provide an easy transition of the sheets from the cutting machine to the denesting table. The solution would also need to enable a safe and effective means of denesting the parts with minimal operator aid.
Material Test
Having previous experience with manufacturing denesting tables, NAVCO suggested to the customer that a material test be performed. Each company has unique tolerances, part shapes, and part sizes that influence the difficulty of denesting the parts. Performing tests of the customer’s sheets, NAVCO is able to determine if a table is a viable option. If it is, data is gathered to determine what settings, and other modifications can be made to maximize efficiency and effectiveness.
The customer agreed with NAVCO’s suggestion that a material test of the sheets be performed. NAVCO engineers coordinated with the customer to have their sheets sent to the material testing lab at NAVCO’s manufacturing facility. The sheets were tested using a vibrating table and a full report of the results along with videos of the test were created and shared with the customer. During these tests NAVCO found that a vibrating table would be able to denest parts from the sheet within the required time. The engineers performing the test were also able to identify changes to the table settings and sheet placement that would improve the speed at which a sheet could be denested.
Fully Custom De-Nesting Table
Combining the data and information gained from speaking with the customer about their application requirements with the results of the material test, NAVCO’s in-house engineering team put together a custom vibrating table tailored to the specific needs of the project. The table would be comprised of a vibrating clamp platform and a static transfer table. They would work together to provide a complete custom unit designed to fit within the customer’s application meeting all their requirements.
Static Transfer Table
The static transfer table will be used to hold and transfer the sheets as they come on and off during the denesting process. It will allow for easy movement of the sheet skeleton and control of the parts once they have been removed from the sheet. To facilitate this the system includes:
Ball Transfer Plate
A ball transfer plate was utilized to enable free movement of the sheets over the table. It will allow the operator to easily position the sheet into the clamps and on the table. Once complete, the ball transfer plate allows for easy transition of the skeleton to the scrap bin located next to the table.
Pneumatic safety guard in lowered position.
Pneumatic safety guard in raised position.
Pneumatic Safety Guard
A pneumatic safety guard was added to help control the parts during operation. The guard starts flush with the table edge to allow the sheets to be transferred to the table without getting in the way. Once in position the guard is enabled and raises 4 inches, preventing access to pinch points during table operation.
Denesting Table
The denesting table will be used to provide vibration to the sheet. It will be designed to nest within cutouts in the static table.
Pneumatic Heavy Duty Clamps
Pneumatic, heavy-duty clamps were added to clamp the sheet in place and transmit vibration directly into the sheet.
Pneumatic air spring lifts in lowered position.
Pneumatic air spring lifts in raised position.
Air Spring Lifts
During the material test it was determined that lifting a side of the sheet reduced the total denesting time. Air springs were incorporated to lift the clamps and rotary electric motors. This allows the vibration to be imparted into the sheet while lifted and works to isolate the vibration from the table stand.
Rotary Electric Motors
Rotary electric “unbalanced” motors were utilized as the drive mechanism. The motors were sized to create the appropriate acceleration on the range of sheet weights provided by the customer.
Control Panel
A user mountable control panel was included with a variable frequency drive (VFD) and switches to control the clamps, safety gate, lifting, and start/stop. This simple interface ensures ease of training and operation.
Factory Acceptance Test
Once the table was manufactured, representatives from the customer came to NAVCO’s facility to witness a factory acceptance test. Using sheets provided by the customer, four sheets were denested. During this test safety, design, and performance metrics were evaluated by representatives. The table passed the factory acceptance test, fully meeting the safety and design requirements while also, coming in well under the required 5-minute de-nesting time with an average time of 48 seconds over the four sheets, and the longest sheet only taking 1 minute 15 seconds.
The customer elected to have a NAVCO technician on site during the commissioning of the denesting table to ensure proper installation, operation, and training of personnel on proper maintenance practices. The commissioning of the table went smoothly, and the denesting table is now operational and fully incorporated into their process.
