If sections of different thicknesses are required, make the transition as smooth as possible using a chamfer or fillet. This will allow the material to flow more evenly through the mould.

When certain sections cool (and as a result shrink) faster than others, then the part can permanently bend due to internal stresses.

I have to ease up on the injection on his as the molds are vented so well.  I need to cull the older ones and obtain more of BJ's Stickem.  Shooting bot brand of molds at a time throws my rhythm off in the area of pressure.

I can shoot BJ's longer as it takes them longer to get too hot while on the older ones I have to cease after 60-70 sticks, too hot and incomplete baits.

I have other molds that are MUCH thicker bodied baits and therefore should have more of a problem with denting and I almost can't make them screw up but those stick molds are just a pain in my anus haha! I do use the HDA instead of salt, don't know if that would make a difference or not??

When adding text choose embossed text over engraved text as it is more economical when creating the mould. Raising the text 0.5mm above the part surface will ensure the letters are easy to read.

When even the maximum recommended wall thickness is not enough to meet the functional requirements of a part, ribs can be used to improve the strength and stiffness of a part.

BTs are good molds, they make a stick that will catch fish but it is like comparing a Lexus with a Toyota, a caddy to a chevy.

maybe try lower temps? hold pressure  an make sure u top off molds. Sounds like you have an older mold from when bob was there and a newer model that kevin made. I don't personally have experiebce with newer model but i have 9  older ones anywhere from 3" to 5" and they all shoot good. Some one that used to work there told me that bt stick molds have to small of a gate . But i never had a problem.maybe open it up some?

I have them, 6 to be exact.  compared to BJ's new Stickem molds, no comparison I am afraid.  Then venting on BJ's is amazing.

When designing ribs, use a thickness equal to 0.5 x the main thickness, define a height smaller than 3 x the rib thickness and use a base fillet with a radius greater than 1/4 x the rib thickness. Also make sure to add draft angle!

Redesigning the part to remove undercuts or moving the part line can be possible solutions to make the design more feasible.

I bought them in the last year but they were used (from two different sellers) so I have no idea how old they are. The fact that the molds are not the same size leads me to believe they were made at significantly different times.

Injection moulding is a manufacturing process that melts, injects and sets plastic into a metal mould. The plastics used by injection molding processes are relatively cheap and can be used to achieve a wide variety of properties, so injection molding is popular for creating many packaging and consumer products, like LEGO!

When 2 flows meet, small hair-like discolorations may develop. These knit lines affect the parts aesthetics, but also they generally decrease the strength of the part.

To avoid warping and sink marks on the part as the melted material cools down it is important to have uniform wall thicknesses and avoid thick sections if possible.

As the plastic shrinks, it applies pressure on the mold. During ejection, the walls of the part will slide and scrape against the mold, which can result to drag marks.

When the interior of a part solidifies before its surface, a small recess in an otherwise flat surface may appear, called a sink mark.

Has anyone used the 5 inch Basstackle injection stick bait mold ? If you have , what were the results ( good and bad .)

Draft angle is a taper applied to the vertical walls of the component to be moulded to assist with releasing the part. Walls without draft angle may become stuck in the mould and will have drag marks on their surface.

Thick sections can lead to various issues such as warping and sinking. Reducing the maximum thickness of the design can be achieved by making the thicker sections hollow is essential. To improve the strength of these sections, ribs can be used to create structures that are of equal strength and stiffness but with reduced wall thickness and weight.

I have herd that guys have had the same issue you are talking about! Most have said the gates are to small. Some have said that the nice shape at the top of the bait is great , but the small gate causes the dents .

I have 2 of the 4" stick molds from Bass Tackle. They are the most problematic molds I have. Obviously it's just me if everyone else doesn't have problems. I just can't seem to get 4 nice baits ever. Always one or more that dent or not shaped right. But as I said, it must just be me.

The uniform wall thickness limitations also applies to edges and corners; the transition must be as smooth as possible to ensure good material flow through the mould.

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Trapped air in the mold can inhibit the flow of the material during injection, resulting in an incomplete part. Good design can improve the flowability of the melted plastic.

Commercially, injection moulding offers a flexible, consistent and cost-effective process of manufacturing that allows for rapid production of parts in a range of materials. Once the process has been set up and tested, machines can produce thousands of items per hour and once the mould is created (which is the most expensive element) the cost of production per component is relatively low.

Bosses consist of cylindrical projections with holes designed to receive screws and other fasteners and assembly hardware, they are very common in injection moulded parts as they are used as points of attachment or assembly.

For interior edges, use a radius of at least 0.5 x the wall thickness. For exterior edges add a radius equal to the interior radius plus the wall thickness to ensure constant thickness everywhere. This can also help to stop stress concentrating in the sharp corners which can cause weaker parts.

Undercuts refer to part features that cannot be manufactured with a simple 2-part mould because material is in the way while the mould opens or during the ejection of the part. Avoiding undercuts all together is usually the best options as they add cost, complexity and maintenance requirements to the mould.

I have 2 of the 4" stick molds from Bass Tackle. They are the most problematic molds I have. Obviously it's just me if everyone else doesn't have problems. I just can't seem to get 4 nice baits ever. Always one or more that dent or not shaped right. But as I said, it must just be me.

The outer diameter of the boss should be 2x the nominal diameter of the screw or insert and its inner diameter equal to the diameter of the core of the screw.

Injection moulding typically produces parts with tolerances of +/- 0.25mm. Tighter tolerances can be possible in certain situations but increase the cost of manufacture dramatically.

Here at UNSW we have 2 CR Clarke desktop injection moulders great for learning, testing and experimenting with the process!