1, Application of error proofing device technology on equipment
In the manufacturing process ofauto parts, the technology application of error proofing device on the equipment mainly includes the following categories:
(1) Qualitative error proofing
Through image recognition technology, photoelectric, limit, logic control technology of proximity switch, etc. to complete error proofing, such as: real-time photo comparison: distinguish whether the direction of assembly parts is correct;
Sensor sensing detection: according to the shape change of different product models, the machining automatic line will feed back the sensed information to the subsequent processing procedures, so that the subsequent processes call the corresponding processing procedures and implement the corresponding processing contents;
Machining hole detection: in the position after drilling or tapping in the machining line, detect the cutting edge of the machining hole and wash the chips;
Hard backer: recognize the front and back flow direction of the workpiece. For example, in the feed port of the automatic processing line of the cylinder block, use the width difference between the front and rear end faces of the cylinder block to set the hard backer to ensure that the front end direction is in front when the cylinder block enters the machining line
Hard probe: detect different models of parts, implement different assembly or processing technologies, such as probe to detect the shape of parts, implement different assembly, such as hard probe to detect cylinder hole, distinguish 3.0L or 3.4L cylinder block;
Guide block: distinguish the conveying guide of parts;
Grating error proofing: through the detection and control of grating, whether the workpiece is placed in place;
Fixture error proofing: control whether the assembly parts are placed in place on the fixture to prevent errors.
(2) Quantitative error proofing
The purpose of error proofing is achieved by measuring the measurement technology (gas flow converted to electricity) induced by the probe or converted by gas electricity, such as:
Feedback of ruby probe detection data: the inner diameter of pressed valve seat ring is detected by ruby probe to distinguish whether the parts are 3.0L or 3.1l cylinder head of auto parts;
BTS tool length detection: CNC machining center tool detection can prevent the wrong length of the tool installed in the magazine, prevent the phenomenon of tool breakage in the process of machining, and reduce the occurrence of the first workpiece or waste products in the process of machining;
Air hole pressure detection of positioning surface: error proof measures to confirm the workpiece is in place correctly;
Leakage test: online test of automobile parts such as cylinder head, oil channel of cylinder block and water channel, etc. to control the leakage into the next process;
Diameter measurement with line inspection tool: it is widely used in the position after boring and reaming in the automatic machining line, to control the appearance of unqualified products 100%;
Torque control: the tightening degree of automobile parts such as many bolts is controlled by torque gun.
(3) Error proofing of vibration function
Through the vibration of the vibrating machine, the parts are continuously vibrated and transported to the place where the direction of the parts is correct. Only when the parts are in the correct position direction, they can enter the feeding track. The parts with the wrong position direction fall into the vibrating material box of the parts, so as to prevent the wrong feeding direction of the parts and avoid the scrapping of the parts. For example:
Verify the direction of cylinder camshaft bushing to prevent the bushing from being pressed reversely;
The press fitting direction of the cover of the cylinder block water channel is error proof, etc.
2, Material error proofing
Error proofing of workpiece holding device: the processed products are placed in a fixed position in a directional way to prevent the collision between the workpiece and ensure the surface quality of the processed parts;
Color code error proofing: the storage rack of parts in the assembly area uses color code error proofing.
3, Manual error proofing
(1) Establish standard operation SOS: for example, finished products, products to be processed, waste materials, industrial wastes and other offline parts in the processing process, they must immediately hang identification labels of different colors according to the processing specifications of various parts (see Figure 9), set the normal use durability of the cutting tools, establish TPM, PM maintenance system in case of wrong installation, etc;
(2) Tool installation and error proofing: the operator adjusts the tool according to the tool change specification, such as checking the tool number and comparing the length of the tools, so as to prevent unqualified parts caused by errors in tool adjustment;
(3) Visual inspection and measurement error proofing of workpiece: the operator shall check visually according to the inspection frequency and measure the defects existing in the workpiece processing and the blank itself, remove the unqualified workpiece, and make it offline in this station.
★ level of error proofing technology
According to the error proofing effect, the error proofing technology can be divided into the following three levels:
(1) Error proofing without manufacturing defects, that is, it is impossible to make bad parts, and the number of parts that may be damaged is zero;
(2) Error proofing without transferring defects, that is, it is impossible to transfer bad parts to the next station;
(3) Error proofing of defects is not acceptable, i.e. the subsequent station will not accept bad parts
The ideal state of error proofing technology is error proofing without manufacturing defects, which is the most active, economic, predictable and error prevention control technology. For example, the detection of probe, guide limit and sensor induction before machining can avoid manufacturing defects. However, due to the possible defects or the different causes and the functional layout of the machine tool and other reasons, it is inevitable to adopt the other two error proofing technologies that do not transfer defects and do not accept defects, which are also the most passive and expensive error proofing measures. The CNC machining center and the drilling station of the machining automatic line can detect the tool breaking after machining in this station, which can reach the goal of not transferring defects; the detection and error proofing of the detection station after the drilling and tapping processing in the automatic line can only reach the goal of not accepting defects.
