一,The purpose and types of die springs
Mould springs are mostly employed to give the mould the force it needs to close or open, making sure that mould sections may be easily reset or punched. Mould springs can be split into numerous groups according on their uses:
Compression spring: the most frequent type, utilised for ejector parts, moulds, resetting ejector pins, and more.Stretch spring: utilised for the reset mechanism or the mould pull rod.Torsion spring: Gives some particular mould structures a twisting force.Combination spring: utilised to handle composite loads or pieces that are stamped with a lengthy stroke.Knowing how springs are classified will help you figure out what kind of force is used when choosing hardness and lifespan
二, How to choose the right hardness for a die spring
1. Amount of work
Light load scenario: For small stamping dies or plastic moulds, springs with reduced hardness (HRC 35–45) can be chosen to make sure that the springs are flexible and easy to work with.
In heavy-duty situations, such steel plate stamping dies or continuous stamping dies, you need to choose high-hardness springs (HRC 45–55) to make sure they don't simply collapse when the pressure is high.
2. Spring material
Some common materials are 60Si2Mn, CrSi, SUS steel, and 65Mn. Different materials wear down at different rates and last for different amounts of time:
65Mn: Strong, resistant to wear, and good for moulds that hold medium to heavy loads.
60Si2Mn: Not very hard, good for plastic moulds or stamping moulds with light loads.
SUS304/316: Resistant to corrosion, good for moulds used in culinary, medical, or other specific settings.
3. Working temperature and environment
When using high-temperature moulds, you need to think about the thermal softening effect and make sure the hardness is raised enough.
When working with corrosive materials like chemical plastics or moulds that include salt, you should use stainless steel springs.
三, How to test the life of a die spring
1.number of cycles
There are mainly two types of mould springs:
Short life spring: cycles < 500,000 times; good for small batch or non-continuous production.
Medium life spring: 500,000 to 2 million cycles, good for regular production lines.
High lifespan spring: may last for at least 2 million cycles and is good for continuous manufacturing and high-speed stamping dies.
2. How stress is spread
The life of a spring is closely connected to the stress it is under while it is working.
To prevent going beyond their fatigue limit, springs should operate as much as possible within their elastic limit. If they do, their lifespan will be greatly decreased.
3. Treatment of the surface
Surface treatment can make springs last longer:
Polishing treatment: lowers the number of microcracks and stress points.
Nitriding, galvanising, and nickel plating make things more resistant to wear and corrosion.
Passivation treatment: This is good for stainless steel springs since it makes them more stable in chemicals.
4.How to use and take care of
Check the spring for deformation, cracks and wear and tear on a regular basis.
For moulds that carry a lot of weight, it is best to utilise extra springs to keep individual springs from breaking too soon.
四,Suggestions for improving hardness and lifetime
Make sure the hardness and load are about the same. If the hardness is too low, the structure could collapse, and if it is too high, it could break easily.
To make the spring last longer, use high-quality materials like high-strength alloy steel or stainless steel that doesn't rust.
Treatments that reinforce the surface, such polishing, nitriding, nickel plating, and others, can make the service life much longer.
Make sure the spring size is right by figuring out the mould space and stroke, the spring diameter, number of turns, and free length. This will make sure that it works within the elastic range.
Regular replacement and maintenance: For manufacturing lines that run a lot, it's best to replace them every so often to minimise mould downtime and losses.
五,Common Misconceptions and Precautions
The harder it is, the longer it lasts
In fact, being too rough might cause brittle fractures and limit the lifespan. It should be chosen depending on the workload and cycle count as a whole.
Is a spring with a bigger size more durable
springs can hold a lot of weight, but if the design isn't good, they may still fail early due to fatigue.
Can surface treatment take the place of choosing materials
Surface treatment can make things last longer, but it can't change how flexible or strong the material is. Choosing the right material is still the most important part.