How to design an injection mold for 90 degree elbow?

//How to design an injection mold for 90 degree elbow?

How to design an injection mold for 90 degree elbow?

90 degree elbow injection mold

As shown above, this is our company’s recent mold project- 90 degree elbow mold . An injection mold for the production of plastic bends. For plastic elbow molds, the core structure is essential. We use the collapsible mold core, since the structural characteristics of the product different from the traditional PVC 90 degree elbow. Let’s look down.

Mold and parameters


The picture above shows the overall appearance of the mold. The Mold size CI3540. How about it? It is like a big hammer. Slider and hydraulic cylinders to make it look very prominent . Take a look at some of its parameters:

Part informationTool information
Part name220FSWP90StandardDME
Part NO:TypeTwo plate
Shrinkage rate1.01Insert steelH13(HRC48-52)
ColorBlackRunner typecold runner
Surface finishCavity :SPI B3, Core :600# SandpaperGate typeSide gate

Product Analysis

Although it is not a big guy. Its structural characteristics have caused us some trouble. Now let’s look at the product.


There will be two straight sides on the finished product,the slider cannot slide out directly due to the bend in the product,this is why we have to design a special mold structure for releasing the mold.

“Oh, this is a small challenge.” This is the result of thinking about our mold design for an hour. But we are happy to challenge ourselves. And we can learn some of our own cases. Before that, we also made a lot of plastic elbow molds. Including 180 degree elbow, 45 degree elbow, 30 degree elbow, tee or cross, and other plastic fittings.

The design analysis of the mold

According to the product requirements,our engineering department designed an innovative mold structure to solve the issue of mold releasing. The mold will need two sliders for this product, as you can see the image to the right, the first slider is only for the straight section, the second slider needs to go straight and then rotate the core inserts out of the part.


Mold slider structure

Now let’s take a look at the overall structure of the slider:


Collapsible core

For the mold smoothly,we have to separate the Second slider into 3 core inserts. see below
The figure below shows the structure of row 2.

plastic 90 degree elbow

To make the product release from the mold smoothly ,we designed and manufactured three pivoting core inserts. It depends on the arc length of the elbow and it has two straight area.

Ok, let’s look down.

Mold fixed side and moving side

slider structure of plastic 90 degree elbow mold

The slider comes out view. We control the entry and exit of the slider through two wire ropes.

fix mold of plastic 90 degree elbow mold

Let’s look at the structure of the fixed side. The mold core contains a threaded insert.


I can only talk about so much about the design of the mold. We reserve more details, because the company needs. thank you for your forgiveness.
Maybe this is not the perfect solution, in fact we have succeeded. If you have a better idea, you can talk to us.
If you have a manufacturing need for a plastic elbow mold, you can contact us. We will respond to you within 1 hour.


Look down!

Practical application of the mold

Let’s take a look at the performance of the mold in practical applications. The video below is a motion demonstration of the mold slider. Collapsible core is very smooth.

The video below is the production of plastic elbows. We use a 200T injection molding machine. In order to meet the requirements of injection pressure and amount of glue.

Finally, look at the finished product.

There are no defects in the product, and no depressions inside the tube. The threads mesh well with other accessories. The word mark is very clear.


At the end

The mold took us more than 40 days to complete these things. Although it has encountered some trouble, it has been overcome. Now the mold has been officially put into production, producing 600pcs per day. Outstanding

This is just one example of our curved tube mold, and we will update more cases later. Stay tuned.


We are professional manufacturer of plastic elbow die. Whether it is a 90 degree elbow / a 120 degree elbow / a 360 degree elbow or a variety of non-standard angle elbows. And all kinds of water pipe joint Plastic molds. We can also injection molding plastic elbows, such as PVC / pp + GF / PC + GF / PA + GF / ABS.

three-way PVC pipe fittings
pvc pipe fitting

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