Top Injection Or Side Injection Molds

[Groucho]

what are the pros and cons to each -top injection or side injection molds.There are molds that I can either way and don't know which would be better. Thanks

[Painter1]

Top injection molds are best if you want to inject 2 colors. The downside is that you need to inject each cavity separately. Side injection mold cavities are filled from a single port. Also consider laminate plates for 2 colors.

[emptystringer81]

Not sure if ive ever seen a top injection mold, Correct me if I'm wrong but isn't most mold all side?

[archery1]

there are some molds that are top inject they have a port per each cavity. makes makin laminates easy an consistent  just more time movin inj to each port. most side inject molds will make good laminated baits(most) but not all I would check with mold maker b4 I buy if laminates work with the particular mold.

      Seems to me the less the cavities a side inject mold has the better the laminates work , but if you wanna make swirls the more the cavities the better

Edited December 23, 2015 by archery1

[Apdriver]

Mostly it's your swimbaits that you want top inject because of how the CNC has to cut them. If they make them side inject and you try to laminate that bait with a twin injector, it will laminate left side one color, right side the other color. In nature, usually the top is darker, not one side. The work around is to make an injection port on each cavity and you can rotate your blending block so your dark color fills the back or top of the bait.

Here's a pic with a top inject mold and the swimbaits to give you an idea. They say a pic is worth a thousand words.

[Apdriver]

Now let's look at a side inject single port mold in a jerkbait where the cavities are laid out differently in relation to the runner. When we laminate this bait, we have the two colors flowing down the runner and the colors flowing into the top and bottom of the baits. The only orientation you need to worry about is the top and bottom of the mold and which color goes on top. Hope all this makes some sense.

[fishon-son]

two nice looking baits....apdriver

[Groucho]

thanks for all the info

[emptystringer81]

Those look great, love that mold. I don't understand how it flows down the shoot pipe and don't swirl around, its a mystery lol

Now let's look at a side inject single port mold in a jerkbait where the cavities are laid out differently in relation to the runner. When we laminate this bait, we have the two colors flowing down the runner and the colors flowing into the top and bottom of the baits. The only orientation you need to worry about is the top and bottom of the mold and which color goes on top. Hope all this makes some sense.

[Frank]

It's a flow thing as long as the viscosity is close it won't mix unless it is provoked to. Hook slots are a real problem for this kind of stuff. Shallow ones are better but it still might cause a small swirl at times. Lower temps are less susceptible to this type of stuff. Slow steady pressure helps a lot too.