Production Process
Mechanical product refers to the production process from raw material to the entire machinery factory production process. It includes: blank manufacturing, machining, heat treatment, assembly, inspection, testing, painting and other major production process; also includes the packaging, transportation and other auxiliary processes.
Now I'll briefly introduce process of making the crane, at the same time, you may have a preliminary understanding of our equipment.
Crane from the metal structure (the main beams, side beams, platform and ladder railings, small frame, etc.), machining parts; purchased parts (bearings, fasteners, standard parts, etc.) and spare parts (due to our equipment or capacity reasons, the commission units processing components: If the hook) made through the assembled product.
Production process for current each structure:
1. Incoming inspection:
Inspection of the incoming material: it means that quality inspection department will check if the incoming materials (including steel, welding material) have certifications, verify them in accordance with the national standard and company. Recheck if necessary, conduct random inspection chemical composition and mechanical strength will be inspected by random samples to see whether
2. Pretreatment Of Steel Surface
Before cutting of the steel, shot and ball blasted, surface of important parts reach degree Sa2.5 of GB8923 standard. After removing the rust, paint anti-corrosive primer at once.
3. Primer Painting
Primer spray will be painted immediately after shot blast to avoid rust of the surface.
4. Marking Off
Mark the shape and processing lines on plate with sample plate, handrail or diagram.
5. Plate-cutting
CNC cutting, semi-automatic cutting, shearing and sawing. Processing department will choose the appropriate cutting method, draw up procedure card, put in program and number.
6. Plate Connection
Some parts (such as web plate of main girder) will be connected by several plates. Plates will be connected according to size, mark and process requirements. Weld will be bevel cut by semi-automatic cutter and then treated by automatic submerged-arc elding .
7. Flaw Detection
Butt weld seam will be detected according to requirements because of its importance, grade is no lower than II regulated in GB3323, when detected by ray, and shall be no less than Ⅰ regulated in JB1152 when detected by ultrasonic. For unqualified by parts, shaved carbon arc gouging, re-weld after cleaning.
8. Leveling
Leveling: level the plate after connecting,
Method:
(1) Mechanical leveling: equipment: roller plate leveler W43Q-32X2500
(2) flame straightening
(3) manual correction
9. Secondary Mark, Cutting
After connecting, detection and leveling, draw cutting lines (marking off) according to the required shape, size, cut them with semi-automatic cutting machine.
10. Assembly:
Take main girder as an example, assembly procedure as follows:
① Build platform: assemble it on the platform, flatness no more than 1 / 1000
② Web plate will be put on the platform, weld longitudinal reinforcement angle, generally it's double-staggered intermittent welding;
③ Cover-Plate will be tiled on the platform, mark the position of rib and web plate.
④ Weld the ribs according to dot line on plate, apply manual and CO2 spot welding;
⑤ Weld main and aux web plate on cover plate which will be "π" shape beam.
⑥ Weld seams inside, (ribs, web and cover plate); (gas-welding), then paint antirust primer;
⑦ After marking on platform, put "n" shape girder on lower plate; weld seams inside;
⑧ Weld four main seams (automatic submerged-arc welding) and other seams (gas protection welding).
⑨ Correction, limitation. Generally VSR will be used for large components, camber of main girder shall be 0.9-1.4S/1000 (S stands for span).
11. Flaw detection and inspection
Ultrasonic flaw detection is carried out on the main welds, and the four long welds of the web and the cover plate shall meet the defect classification level II standard specified in GB/T12469. The structural size meets the requirements of the drawings, and the camber is within the specified range.
12. Assembly (assemblage)
Assemblage means assemble each part according to requirements.
When main girder and end carriage are connected into bridge, assure that distance between center of two track and length tolerance of bridge diagonal line meets requirements.
When assemble LT and CT mechanisms.
Machined parts production process:
1. Production process of machining parts
Rough parts: they mainly include cast steel (ZG270-500,ZG340-640 etc.), iron casting (HT, QT), welding (steel plate and welding parts), round steel parts (cut by saw machine.
2. Machining
it means machine mechanical components in different method (milling, planing, grinding, boring, drilling, insertion, etc.) to change shape, size, surface roughness of them into qualified ones.
3. Assembly of electric
Assembled by electrician.
4. Bought out item
Items (mainly including motor, reducer, bearing, standard fastener, electrics and other standard parts) will be bought according to configuration table prepared by designing department and schedule made by process department. Assemble each part according to drawing.
5. Cooperation part (including rough parts such as cast steel, iron casting, forgings and overall spare parts)
because our facility and production ability are not enough, some parts will be designed by us and made by other manufacturer. They will be checked when come to our site.
At present, cooperation parts include hooks, pulleys, part of drums, cast steel, iron casting, forgings, etc.
6. Final assembly
Assemble each part according to general drawing, such as assemble of hoisting mechanism on trolley, pulley and support stand, traveling mechanism, etc. Some parts have to be removed for convenient transportation, and assemble them at site, but have to be trial erected at manufacturer's site, set welding positioning block on appropriate location for positioning of the second assembly. Some parts such as stairs, handrail will be installed at user's site, decide which part will be installed at user's site according to specific circumstances.
7. Inspection
After final assembly, quality inspection department will inspect completely according to relative standard and technical requirements, issue ex-work certificate if it's qualified.
8. Paint
Choose different paint (color, type) according to contract or working environment; Process department shall prepare color and type of the painting (type, color, quantity, thickness of primary and finish coat, etc.) according to requirements of the contract. See paint used in various environments in table 2.
9. Paint inspection
When painting is finished, check if film thickness meets requirements, no defect such as sag or crinkle, above is the manufacturing process of the crane.
10. Delivery
Transport the product to user.
11. Site erection
12. Acceptance
Manufacturing process of the products is finished.