Safety points for mold lifting and flipping fixtures

Safety points for mold lifting and flipping fixtures
The risk of mold lifting is concentrated in the deviation of the center of gravity and the failure of the lifting point. When the wheel hub mold weighing more than 6 tons is flipped, the center of gravity deviation can reach 200-300mm.
First, calculate the center of gravity position
The center of gravity of the wheel hub mold is usually biased towards the thicker side of the mold frame. After assembly, the center of gravity may deviate from the geometric center by 100-300mm.
The center of gravity position should be marked on the drawing. The unmarked molds need to be confirmed by trial lifting method before the first lifting.
During the trial lifting, lift 100-200mm off the ground, observe the tilt direction, and then adjust the lifting point. Lifting directly to a high place carries too much risk.
Specification for suspension point design
The number of hanging ears is usually 4, symmetrically arranged. The rated load of a single lifting lug should be greater than 1.5 times the total weight.
The hanging ear weld seam needs to be inspected by non-destructive testing. The fatigue strength of the fillet weld is lower than that of the base metal, making it a high-risk area for lifting failure.
When the weight of the mold exceeds 10 tons, it is recommended to use a dedicated lifting beam to avoid excessive angle between the steel wire rope. When the angle exceeds 90 degrees, the horizontal force component will significantly increase.
The function of flipping tooling
Mold maintenance often requires flipping 180 degrees. Without specialized tools, relying on the inclined pull of the crane can easily cause slippage.
The flipping fixture consists of a flipping frame and a clamping mechanism, with a cost often ranging from 20000 to 50000 yuan. Suggested configuration for large-sized molds.
When delivering the wheel hub mold, Xinfeng Mold will provide a lifting point diagram and recommended lifting specifications for customers to configure the tooling.
On site requirements for lifting operations
The work area should be cleared and personnel are prohibited from staying under suspended objects. This is a basic safety requirement.
Before lifting, check the wear of the steel wire rope, shackles, and lifting ears. Wire ropes with more than 10% broken wires should be scrapped.
Stop outdoor lifting when the wind speed exceeds level 6. Indoor work should also pay attention to the stability of the driving track.
Causes of Common Accidents
The first type is torn hanging ears. Due to the lack of non-destructive testing of welds or insufficient load estimation.
The second type is wire rope slippage. Due to the lack of anti slip structure or excessive angle at the suspension point.
The third type is flipping out of control. Due to the unconfirmed center of gravity, the center of gravity crossed the pivot point during the flipping process.
Daily Management
The lifting equipment should establish a ledger to record the purchase date, rated load, and inspection records.
Conduct a quarterly inspection of lifting equipment, with a focus on welds, wear, and deformation.
Operators should hold certificates before taking up their posts. Unauthorized operation is one of the main causes of accidents.
Review of lifting plan
For molds weighing over 6 tons, the lifting plan should be reviewed by the equipment and safety department to clarify the lifting points, lifting equipment, command and warning range.
Recording and Training
Records should be kept for each lifting operation, including mold number, weight, lifting equipment specifications, and operators.
Practical tips
When storing the mold, use a dedicated bracket and do not directly land it on the ground. The moisture on the ground will accelerate the corrosion of the bottom of the mold frame.
Hold a brief briefing before lifting operations to clarify command signals and evacuation routes, which can save a lot of trouble in five minutes.
Frequently Asked Questions
Q: How to determine the center of gravity of the mold?
Answer: Drawing annotation or actual measurement using trial lifting method.
Question: How many hanging ears do you need?
Answer: It is usually arranged in four symmetrical positions, with a single load left at 1.5 times.
Q: How much does it cost to flip the tooling?
Answer: It is usually between 20000 and 50000 yuan, and it is recommended to use large molds.
Q: How long does it take to replace the steel wire rope?
Answer: If the wire breakage exceeds 10%, it will be scrapped, not according to the time.
Q: Is there a requirement for the lifting angle?
Answer: It is recommended not to exceed 90 degrees, as excessive horizontal force will increase.
Q: Do we need to perform non-destructive testing on the hanging ear welds?
Answer: Yes, the fillet weld is a high-risk area for failure.
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