Assemble die‑cast components without thread failures
Assemble die‑cast components without thread failures
Assemble die‑cast components without thread failures
As the trend toward electrification and energy efficiency accelerates, industries such as automotive, electronics, and lighting, among others, are increasing their demand for lightweight materials. Lightweight components enhance performance and efficiency while reducing resource consumption and emissions. Die casting makes it possible to produce strong, lightweight components with precise geometry, but assembling these parts introduces unique challenges.
Challenges in assembling die‑cast parts
Assembling die‑cast components can be challenging because of how screw holes are formed during the casting process. In die casting, holes are created by a core pin with a small draft angle (α), so when molten metal flows around the pin, the resulting hole reproduces its slightly conical shape rather than being perfectly cylindrical. (Fig.1)
During screw installation, the tight, conical hole generates high pressure and friction, which causes the aluminum to adhere to the screw threads. (Fig 2)
Why draft angle is important in die casting?
- It facilitates part ejection from the die and reduces the risk of sticking.
- It prevents surface scratches, minimizes rework, and extends tool life.
- The cavity maintains its geometry and surface finish for a longer time.
Blockage and thread stripping during installation
When a screw is inserted into a tapered or conical screw hole, uneven thread engagement occurs along the hole depth: the upper part of the hole has low engagement, while the lower part has higher engagement. This uneven load distribution can cause assembly issues:
- Thread Stripping: Limited engagement at the upper part reduces resistance to stripping and loosening.
- Blockage: High friction at the tighter zone of the hole leads to screw blockage and galling (cold welding).
These assembly issues can lead to line stoppages, costly rework, and production delays.
Do you experience challenges when assembling die‑cast parts? We have the solution.
Inconsistent draft angles in die‑cast hole
Core pins wear down over time due to erosion from molten metal flow, thermal cycling, and abrasion. Therefore, different pins may wear at different rates and the draft angles can vary widely, with parts exceeding 2º or becoming inconsistent even within the same batch.
Typical workaround approaches - but ineffective
Drilling (and sometimes tapping) the holes
Increases assembly cost due to the additional drilling and tapping operations.
Oversized conical holes
Helps prevent blockage, but reduces stripping resistance.
Applying extra lubricant on the screws
Extra lubrication helps to control friction, but its effect is often inconsistent and inefficient.
The solution for fast, smooth assembly in die-cast parts
At CELO, we provide fastening solutions specially designed for die-cast assemblies and tailored to each application. They help to:
Minimize the risk of screw blockage
Reduce the risk of thread stripping
Provide stable tightening torque
Eliminate drilling and tapping operations, reducing the total assembly cost
Increase pull-out strength and resistance to vibration loosening
Provide reliable clamping force
In addition, we offer screw solutions that optimize assembly time by reducing the number of turns required to secure the joint, resulting in a faster and more efficient assembly process.
Contact our experts to enhance your die casting assemblies.
