Sheet Fluid Forming and Sheet Dieless Forming Part 2.
Posted by: Trent Maki on Friday, March 01, 2002 - 11:18 AM
Fluid Forming Applications to Automotive and Other Industries. A continue report by Mr. Hiroyuki Amino (President, Amino Corp.).
2.2 Fluid Forming Applications to Automotive and Other Industries
2.2.1 Automotive Industries
Fluid Forming applications to the automotive industry offer many advantages in reducing tooling cost, manufacturing operations and the ability to form more complicated shapes.
18.104.22.168 Reduction of Forming Processes
Figures 17~22 show samples of complicated forming of the front section for the Mitsuoka Viewt vehicle. By the use of fluid forming the amount of parts required for the front section were reduced from over ten to just three parts, saving on assembly and welding operations. In addition the overall tooling cost was reduced and part quality improved.
Fig. 17: Mitsuoka, Viewt
Fig. 18: Front Face, draw sample SPCE t0.8mm
Fig. 19: Fender, draw sample SPCE t0.8mm
Fig 20: Front face after trimming
Fig 21: Fender after bending and trimming
Fig 22: Assembled Front Face and Fender
Figure 23 - 28 show samples of the Mitsuoka Galue vehicle. Again, difficult forming in one process of face, hood, fender and mask. There was a significant reduction in parts formed saving on assembly and welding operations. Tooling cost was also reduced.
Fig. 23: Final Product-Mitsuoka Galue
Fig. 24: Front Face Draw SPCE t0.8mm
Fig. 25: Hood Outer Draw SPCE t0.8mm
Fig. 26: Hood Inner Draw SPCE t0.8mm
Fig. 27: Fender Draw SPCE t0.8mm
Fig. 28: Mask Draw SPCE t0.8mm
22.214.171.124 Small Volume Production
As the necessary cycletime to form one piece is high, the Fluid Forming Process is more suitable for small-lot production. Figure 29 shows Toyota Sera, low production sports car.Both inner and outer body panels manufactured used fluid forming.
The production volume is 1000~1500 vehicles per month. The tooling cost is about one third of a conventional system.
Fig. 29: Outer and Inner Body Panels from Toyota Sera
126.96.36.199 Aluminum Alloy Forming
In the automotive industry, aluminum alloy is a possible replacement for steel in order to reduce vehicle weight. However, aluminum has low formability and production by conventional methods is impractical. The Fluid forming process overcomes aluminum forming restrictions and strain hardens the material during forming reducing springback. Figures 30~33 show examples of aluminum automotive panels formed by fluid forming.
Fig. 30: Roof A5182-0 t1.1mm
Fig. 31: Fender A6022-T4 t1.1mm
Fig. 32: Fender A6016-T4 t1.1mm
Fig. 33: Side Door A6111-T4 t1.1mm
188.8.131.52 Reduction in Forming Processes with Multi-Forming Method
Figure 34 shows an oil pan formed by the multi-forming method. In addition to the Fluid Forming tool, a separately controlled punch and die sequences two drawing stages in one operation. The oil pan material is anti-vibration laminate steel.
Fig. 34: Oil Pan anti-vibration laminate steel
184.108.40.206 Forming of Sheets of Different Thickness with the Same Tooling
Fluid forming tooling requires less precision and clearance than conventional tools. Therefore, parts of different thickness as the truck bumper shown in figure 35 can be formed with the same tool.
Fig. 35: Truck Bumper SPCE t2.3 & t1.6
2.2.2 Other Industries
220.127.116.11 High Accuracy
Due to hydraulic pressure pressing the sheet tightly against the punch surface, higher accuracy is obtained in comparison to conventional forming. Fluid Forming is utilized for these samples shown in figures 36~38 for the high degree of accuracy required for uniform light distribution. Figures 39~41 show parabolic antenna and curved mirrors requiring high curvature precision and surface quality.
Fig. 36: Reflector A1080-0 t1.2mm
Fig. 37: Headlight Reflector SPCE t1.0mm
Fig. 38: Various Aluminium Reflectors
Fig. 39: Parabolic Antenna A1100 t4.5mm
Fig. 40: Curved Mirror SUS304 t1.0mm
Fig. 41: Reflector Mirror SUS304 t1.0mm
18.104.22.168 Reduction of Drawing Stage
Complicated shapes that normally require a restrike operation to eliminate the effects of canning, can be drawn in one stage using a moving bead device. A bead fixed to a controlled actuator is applied during the final stage of the draw, effectively performing a restrike operation during the draw stage. Figure 42 and 43 show sinks that normally require four operations by conventional methods have been formed in one stage.
Fig. 42: Sink SUS304 t0.7mm
Fig. 43: Sink SUS304 t0.7mm
22.214.171.124 Radial Assisted Fluid Pressure Deep Drawing
Radial fluid pressure on the circumferential wall of the sheet assists deep drawing.
Figure 44 shows the pressure chamber provided with a bypass that adds push force to the blank as well as lubricates the blank and blankholder face. Figure 45 compares a conventional drawn sample on the left to radial pressure drawing. The draw ratio has been increased from 2.0 to 3.3.
Fig. 44: Radial Assist Draw(2)
Fig. 45: Conventional and Radial Assist Draw
126.96.36.199 Combination Forming-Draw and Stretch
Figure 46 shows an aircraft engine lipskin. By trimming inside of the blank and then clamping the blank on the outside and inside of the punch a combination outer draw and inner stretch forming takes place. By conventional methods twenty processes were required to make this part.
Fig 46: Engine Aircraft Lipskin A2024 t2.0mm
188.8.131.52 Precision Forming with Difficult Materials
Fluid forming can form materials with low formability like stainless steels, aluminum and titanium with precision and accuracy.
Figures 47 and 48 show examples of precision equipment with high surface quality, low strain and distortion, made to exacting tolerances.
Fig. 47: Camera Body SUS304 t0.5mm
Fig. 48: Labtop Base A1100-24H t0.4mm
184.108.40.206 Combination Expansion/Draw Forming
Combining a fluid forming draw and diverting the water pressure to expand the wall, a motorcycle tank as shown in figure 49, can be formed in one process. By conventional means it is manufactured in two parts and welded together. Refer to figure 11 for method description.
Fig. 49: Motorcycle Gas Tank SPCE 0.8mm
220.127.116.11 Prevention of Surface Distortion
Shallow draw panels, as shown in figures 50 and 51, can be formed with less surface distortion. Hydraulic counter pressure evenly applied to the entire surface reduces plain strain.
Fig. 50: Curtain Wall A3003-H12 t2.0mm
Fig. 51: Gas Range Top SPCE 0.8mm
18.104.22.168 Pre-painted/Pre-coated Forming
As there is only hydraulic counter pressure applied on the female side of the die there exists a scenario where there is no metal on metal contact Therefore, less surface scratching and scoring is evident. Fluid Forming is very suitable for forming pre-painted and pre-coated materials as shown in figures 52~55.
Fig. 52: Pre-painted Train Panel A5032-T4 t1.2mm
Fig. 53: Pre-painted Range Hood SPCD t0.6mm
Fig. 54: Pre-painted Fridge Door SPCE t0.6mm
Fig. 55: Teflon Coated Pan A1100 t1.0mm
2.2.3 Flexible Production System
To take advantage of fluid forming in the automotive industry, a new system was developed with Toyota Motor called the Flexible Production System (FPS) FPS reduces the number of required operations to produce a panel from five to three as shown in figure 56. By conventional system a typical fender requires drawing, trimming, bending, cam trimming/flanging and finally cam flanging, to produce a panel. By incorporating a flange in the draw with a distinct bend line, as shown in figure 57, the bending process can be eliminated. In the second stage trimming by laser, as shown in figure 58, combines two processes trimming and piercing. The final stage using a 5-Axis multi-forming device flanging can be performed in one process as shown in figure 59.
Figures 60~62 shows the equipment required for the Flexible Production System.
Fig. 56: Conventional versus Fluid Forming Production System(3)
Fig. 57: Fluid Forming
Fig. 58: Laser Trim and Pierce
Fig. 59: Multiple Forming
Fig. 60: 4000T Fluid Forming Press
Fig. 61: Laser Trimming
Fig. 62: Multi-Forming Press
3.1 Dieless NC Forming Process
3.1.1 Purpose and Outline of Development
The sheet metal industry for some time has been in need of effectively prototyping stamping and producing panels in very low volume. The dieless numerically controlled (NC) machine was developed for just this purpose, as it can form complicated shapes of various materials precisely and efficiently. It as extremely cost effective as tooling is not required and development time is short. Dieless NC forming is suitable for ultra small lot production, rapid prototyping and production of service parts.
A blank is securely fixed to a jig on an X-Y table. Through three-dimensional NC data as shown in figure 63 the table and a vertical tool (Z-Axis) are actuated simultaneously. Shown in Figure 64 the table incrementally descends overtop a fixture and the spherical tipped Z-Axis tool presses on the sheet forming the shape.
Fig. 63: Controller Circuit Diagram
Fig. 64: Equipment Drawing
Main Features of the System
No tool is necessary for forming
Complicated shapes can be formed.
Easy operation with three axes NC programs.
Quiet and safe operation requiring little floorspace
Prototyping is faster and cheaper.
3.1.3 Dieless Process
Figures 65 to 68 show an automotive fender in different stages of forming.
Fig. 65: Start of Forming
Fig. 66: Fender
Fig. 67: Fender
Fig. 68: Final Product
Three different sizes of NC forming machines are available and are distinguished by the size of panel that can be formed.
Figure 69 shows the large type, Figure 70 the middle size and Figure 71 the small type.
Table Size 6500x2500mm
Drive AC Servo Linear Motor
Tool Speed Max. 100m/min.
Max Forming Size 6000x2200x600H mm
Fig. 69: Large, Dieless NC Forming Machine
Table Size 2200x1700mm
Drive AC Servo Motor
Tool Speed Max. 30m/min.
Max Forming Size 2000x1500x600H mm
Fig. 70: Middle, Dieless NC Forming Machine
Table Size 450x450mm
Drive DC Servo Motor
Tool Speed Max. 30m/min
Max Forming Size 400x400x200H mm
Fig. 71: Small, Dieless NC Forming Machine
3.2 Dieless Application to Automotive and other Industries
3.2.1 Automotive Industries
22.214.171.124 Small Lot Production
One of the main advantage of NC forming is that the tooling costs are extremely low, in the order of 5~10% of conventional stampings. However, the forming process is quite slow. Thus this process is suitable for ultra low volume production in the magnitude of 1~30 pieces per month.
126.96.36.199 Service Parts
A major challenge, in the automotive industry, is the necessity of storing tooling for long periods of time. With this new process, those tools could be discarded, and one Dieless NC forming machine can be employed to produce service parts upon demand.
188.8.131.52 Rapid Prototyping
This system is ideally suited for rapid prototyping as development time and tryout cost are greatly reduced. No hard tooling is required and design CAD data can be transferred to the machine controller easily.
184.108.40.206 Automotive Samples.
Figures 72~75 show automotive samples form by Dieless NC forming.
Fig. 72: Fender SPCE t0.8mm
Fig. 73: Fender SPCE t0.8mm
Fig. 74: Exhaust Part SUS430 t2.5mm
Fig. 75: Partial-Inner Body SPCC t1.6mm
3.2.2 Medical Industry
Dieless NC forming is also suitable to the medical equipment industry, where materials with low formability are often used and required in only small volume.
Figures 76 and 77 show an incubator table that is currently in production. Dieless NC machine forms the heater pan, and fluid forming process forms the rest of the table, followed by a trimming and piercing process.
Fig. 76: Incubator Bed; Dieless NC
Fig. 77: Bed; Fluid Forming SUS304 t1.5mm
3.2.3 General Purpose and Other Industries
The dieless process is also ideally suited to the production of intricate three-dimensional designer panels. There is also favorable application to the general purpose and other industries.
Figures 78~83 show examples of NC forming.
Fig. 78: Bath Unit Duraluminium t2.0mm
Fig. 79: Soaker Tub A1050 t4.0mm
Fig. 80: Tapered Hexagon Cups A1050 t1.0mm
Fig. 81: Perforated Design Panel SPC t1.2mm
Fig. 82: Design Panel A1050 t1.0mm
Fig. 83: Boat A5052 t2.0mm
4.1 Future Goals and Trends in the Sheet Metal Industry
4.1.1 Fluid Forming Process
For over thirty years Fluid Forming has been used in production facilities. The utilization of this manufacturing method will continue and even increase in future years. In the near future:
1. There will be an increasing desire by automotive companies to produce specialty vehicles in small volume to suit customer-growing demands.Cost effective production methods will be required. The fluid forming process is well suited due to the reduced tooling cost. The Flexible Production System, FPS, with Fluid Forming, laser trimming and 3-dimensional bending/flanging, will be utilized to increase the production rate.
2. The automotive industry is striving to reduce the weight of vehicles due to environmental pressures New material such as Aluminum Alloys and High Tensile Steels will be used in body panels. As these materials have low formability, fluid forming is suitable to overcome their forming restrictions.
3. There will be an increasing demand for higher surface accuracy and quality.
4 Panels will be formed with pre-painted and pre-coated sheets to reduce production steps and cost. As fluid forming forms sheet with almost unmarred surfaces it will be increasingly used in this area.
4.1.2 Dieless NC Forming
The first Dieless NC forming machine was developed a few years ago and the process is still in the developmental stages. Later this year, the system will be beta tested in an industrial setting.
The purpose of this development is to drastically reduce the tooling cost and development time. The dieless NC forming machine will be utilized in ultra small lot production and to produce service or replacement panels for older vehicles. There is also some merit to rapid prototyping and the production of intricate three-dimensional designer panels in the medical equipment, aviation, general purpose and high-speed vehicle industry.
/1/ Prof. T. Nakagawa Sheet Metal Forming with Hydraulic Counter Pressure in Japan
Prof. K. Nakamura In: CIRP Vol. 36/1/1987, p.191
/2/ Prof. T. Nakagawa Various Applications of Hydraulic Counter-Pressure Deep
Prof. K. Nakamura Drawin
/3/ Y. Suzuki History of Hydraulic Counter-Pressure Forming Machines
In: Japan Metal Press, 11/1997, p.48