1.Heat Exchanger connecting pipe laser welding work station Content
This Heat Exchanger connecting pipe laser welding work station is designed for the laser welding job for heat exchangeer.
This Heat Exchanger connecting pipe laser welding work station adopts FANUC M20iA Robot carrying a TRUMPF (a German company) D70 laser welding head, and Trudisk 2002 laser from TRUMPF. It’s a single working position indexing table type. Each indexing table working position is equipped with one set of welding tooling and one work piece to be welded. The welding tools is pneumatic driven automatic clamping. Work piece is loaded/unloaded manually.
2.Heat Exchanger connecting pipe laser welding work station Designing basis

This Heat Exchanger connecting pipe laser welding work station welding position schematic diagram is underneath. The circles marked in Red color are the laser welding positions.

3.Welding Process Analysis
3.1 Process Flow
According to the characteristics of the external form of S12 product, pneumatic auto fixture is required. The entire laser welding will be completed in one automatic process. Robot, indexing table and and welding single lens coordinate in the process.
Welding procedure: laser deep penetration welding. Welding seam quantity: 4 circles.
3.2 Cycle Time Analysis
Total time for welding 2 work pieces for internal procedure: 3+29+2+28+2=64s
Total time for 2 work pieces for external procedure: 3+36+4=43s.
Single work piece production cycle time is 32s. Working capacity is met.

Details in the cycle time analysis table below.

4. TOTAL LAYOUT OF ROBOT LASER WELDING STATION

4.1ROBOT LASER WELDING STATION Cell Layout (length4500mm×width3500mm×height2700mm) 

4.2 ROBOT LASER WELDING STATION Cell Configuration

No.	Name	Remarks	Brand	Unit	Qty
1	ROBOT SYSTEM	used to robot laser welding		SET	1
	ROBOT ARM	M20iA ROBOT， standard load is 20KG	FANUC	SET	1
	ROBOT CONTROL BOX	R30iB	FANUC	SET	1
	robot teach Pendant		FANUC	SET	1
	Accessory	The cable between the robot and control cabinet (7m), input/output module, robot operating system , anti-crash software, robot software, Device Net channel connector, Profibus adaptor, internet web card	FANUC	SET	1
2	LASER SYSTEM			SET	1
	Trudisk 2002		TRUMPF	SET	1
	2 Channel		TRUMPF	台	1
	Operating Laser cable 20m, 200um		TRUMPF	SET	1
	Water Cooling Machine		TONGFEI	SET	1
3	Laser Welding Head	BEO D70	TRUMPF	SET	1
4	Assisting gas device	Welding seam assisting gas may fluid	JINGGONG	SET	1
5	2 stops range indexer	2 stops range	FIBRO	SET	1
6	Single axis head-tail positioner	Used to weld different position	JINGGONG	SET	2
7	Quick change welding fixture	One welding fixture can fix 2 work pieces	JINGGONG	set	2
8	PLC Electrical Control System	SIEMENS PLC, 12inch HMI + Control Cabinet+BANNER Light Curtain+3-color Light Tower + BANNER Control Button+Cables+Low voltage apparatus+ PHILIPS Lighting + Safety Components	SIEMENS+OTHERS	SET	1
9	Welding Room	Squre tubes welded to form the frame, fixed with steel plates to form a sealed space for robot working area, to prevent danger caused by undesired intrusion.	JINGGONG	SET	1
10	Robot base	Steel welded structure.	JINGGONG	SET	1
11	Safety Protecting instruments	Safety door switch and specialized protection Glass	JINGGONG	SET	1
12	Fume & dust exhausting system	Used to clean the fume and dust	Donaldson	SET	1
13	Weld monitoring system	Camera, screen and install base	JINGGONG	SET	1
14	Work piece deliverying system	Deliver work piece	Modular	SET	2
15	voltage regulator	Ensure stable voltage supply for laser and robot	SHANGWEN/ TENGEN	SET	1
16	Constant temperature & humidity room	provide a constant temperature and humidity environment for laser	JINGGONG	SET	1
17	Others	Spare parts	JINGGONG	SET	1

5.  Main Heat Exchanger connecting pipe laser welding work station Description

5.1  Robot System

In this project, one FANUC M20iA 6-axis-robot and its control box R30iB are used to conduct laser welding. Robot load capacity 20kg, max motion radius 1811mm, re-positioning accuracy ±0.08mm, see pictures below. 

5.2 Laser Power and Welding Head 

Laser power system used here is Trudisk 2002 from TRUMPF, as the following picture.

Laser head is BEO D70 model from TRUMPF, as in the following picture.

5.3 Two Stops Range Indexer

Two stops two work position indexer from German company FIBRO is used. Motor from SEW. Driven by SEW inverter. Motor is with band brake. Indexer rotates anti-clockwise ( rotation direction can be switched to clockwise too). Re-positioning accuracy ±30″.  

5.4  one-axis servo positioner

Head and tail seated structure single-axis servo positioner is used. Rotation encoder is mounted on the non-drive end to control the angle change precisely.  2 electrical fast aerial plugs and FESTO pneumatic fast aerial plugs are equipped on the positioner frame. The positioner has zero point marker and feeding point marker. The tail seat uses a self-aligning bearing with a centre hole. All key position linkages adopt pin/key for position fixing. The following pictures illustrate a posistioner equipped with jig/fixture. 

5.5 Heat Exchanger Laser Welding Fixture

Jig/fixture is designed based on S12 product. The picture underneath shows 2 sets of samples placed on one set of quick change fixture. And the product shell body is placed manually and fixed by positioning pins at both ends. Pneumatic cylinders press tight the shell body and pressing cylinder press tight the work piece from the top, to prevent loosening and falling while the positioner rotates. Connecting pipe is manually placed on top of the locating hole on the pressing block of the rotation pressing block. Sensor detects the work piece in proper position. Rotation pressing cylinder is mounted upside down by a flexible dowel pin beneath the locating hole. They're 2 small holes on each pressing block which cooperate with laser head to finish the laser spot welding of the connecting pipes. After spot welding finishes, rotation pressing cylinder moves, the pressing block lifts and rotates to the side. Laser galvanometer lens will finish the full weld of the connecting pipes. The picture below illustrates the design concept of the fixture. All components and parts of the work piece are detected by proximity detector to determine if they are in position as well as their respective model number. Fixture is equipped with pneumatic/electric aerial plugs and can be quick-changed using 2-pins and 2 bolts.