Dear Friends,
We are mulling over an idea to get manufactured stack molds for Plastic parts used in various appliances which we are manufacturing.

Our purpose of getting stack molds are economy and productivity.

As we have never used stack molds before, please give your inputs about stack molds from the view point of manufacturing cost , efficiency, quality, mold construction, component geometry and molding machine required.

Quick comment to make sure you consider. Stack molds are obviously larger and heavier than the single face molds of your product. Make sure your facility is equipped to handle larger molds of this nature. i.e. crane capacities, tow motor (fork truck), etc.

I'll assume you'll be looking at direct gating with a hot runner of some type. Consider if it's not thermal gate, can it be? Valve gate stack molds tend to be thicker than thermal gate stack molds.

Extended tie bars for your injection press selection, along with any additional pneumatic, hydraulic or mechanical services for the stationary side part ejection of the mold. Consider how the center section of the stack mold will be guided and how it will be supported during mold open/close. Will it ride on the machine ways(spelling?), be supported by the tie bars or self-supporting?

Resins?
Requirements (quantities)?
Is your molding machine capable of running stack tool (clamp and injection)?
Maintenance costs involved?
Tooling costs and ROI?
Ask yourselves these questions before getting involved.
Also it is a good idea to have a good tool maker build these tools, they are not cheap and not a job for a "budget tool builder.
also think of having a single-face backup tool, and not having "all of your eggs in one basket"

KOM

brent

stack molds are a useful idea but let me ask, how big are you intended moldings and how many cavities are required in each mold

Dear Anthony, Our intended stack moulds will be compatible max upto 400 T machine ( Tie bar distance 700 mm). As far as cavities are concerned it will be of total maximum 4 cavities ( 2 in each opening).

Dear Brent,

Our quantities are huge in nos. We are using duplicate mould presently considering the volumes required.

Pls suggest which kind of moulding machines required for processing of stack moulds.

We have our own tool main team, any way how the mould spare cost will be increased in stack moulds?

Normally how much difference in tool manufacturing cost is there ?

Also suugest the right place to get these mould manufactured?

stack mould are made at Aco Mold. A very good tool maker whom I would suggest.
They would take care of all the constraints and full fill your requirements on time..

There are some mold makers in Italy or Portugal that can do a good job for relatively low cost.
German makers of molds and presses can also do a good job, as can HUSKY from North America..
BMB from Italy as well as KraussMaffei from Germany. Also consider Battenfeld and Demag.
I don't think suppliers from China or India can help you with quality molds and machines, but that may have changed recently!

KOM
brent

Comments made by several knowledgable people in this forum are spot on.
Stack molds require longer daylight openings, and you can use the same tonnoge machine as required on a conventional mold. BUT, don't forget your shot size is double for the stack!
Material delivery is another issue that has been mentioned, on a typical stack mold the delivery is usually a hot manifold system in the center section, it will add complexity. More complexity adds up to more oppertunities for downtime and scrap.
Having spent time in the appliance industry, I would question the complexity of the part itself from simple basic questions (IE: Part depth versus daylight requirement), to the more complex questions like side action requirements or undermotion requirements to clear undercuts. Stack molds were used on simpler parts like pails, buckets and Lids initially.
If you are considering stack molds and are starting out with a fresh sheet of paper, requiring the equipment as well you will need a deep pocket to reach into for the expenditure,
Even with financial justification consider the statement above about all of your eggs in one basket. Meaning This: How much production down time can you afford if you have a catastrophic mold or machine failure? Either could mean weeks or even months out of production.

I would add one other "be careful of" to all that have been mentioned
If there is a hang up on just one cavity, it is difficult to spot and running over the shot will almost certainly cause you a headache and lost time - have you considered how you will ensure this does not happen or is this mold run with an operator 7 x 24 and no breaks!!

Hey everyone,
I think plastics processor has to do more with less – less labour, less capital investment, less floor space, and less time.
It has some key benefits of Stack mould plastic parts :
Cost-effective solution for increasing capacity.
Optimum use of shop floor space and machine capacity.
Expanded moulding capacity without capital expenditures.
More output per unit of shop floor labour – higher productivity in your operation.
Thanks

Hey Everyone,
I think stack plastics, injection is a custom plastic injection moulding , specializing in engineering thermoplastics, elastomers and number of other resin including peek and more..
Stack Plastics can create some products as prototypes, short run development parts, all the way up to full production runs with quantities in the millions. From the simplest designs to the most complex, can handle any project.