[Incredilution]

Here's what I would do:

Use a 3D printer to print the frame in two halves. The two halves would be slightly modifyied to have locating pins which allows them to be glued together using a special plastic glue. My stratasys 3D printer will do 10"x10"x10" so your model would fit well in two stages. Some of the smaller machines would require you to split it up in 3pcs.

Then I would make a silicon mold using the assembled/glued printed part. You can buy casting urethane that looks and performs quite similar to ABS plastic. The silicon mold would probably be good for some or all of the 48pcs that you need. The longevity of the silicon mold depends on the durometer and the draft within each comb. The higher the durometer the longer it'll last but the more difficult it is to handle and separate. The good news is, you can use the 3D print to make further silicon molds.

For your quantity, this method will be the least costly and likely the quickest option. The print would take several days and the silicon mold can be done in a day. The 3D print will still be expensive unless you can find someone willing to do it cheap.

[mactec54]

Incredilution

A good idea, but the end product/material have to be Food grade PP,(or similar) So any materials that are used have to be food grade certified

[Incredilution]

Incredilution

A good idea, but the end product/material have to be Food grade PP,(or similar) So any materials that are used have to be food grade certified

Well we would use the P500 ABSi material which is approved for medical applications by post printing exposure to gamma radiation.

Smooth-on sells a food-grade silicon for the mold. You'd just need to find the same for the urethane plastic.

Might still be do-able.

[Deviant]

mactec,

What is the size limitations of your injection molding machine. Is this project something you'd be willing to look at doing?

Do you know much much material runs for polypro

[mactec54]

Deviant

The polyPro for injection molding is around $1 a pound for the resin

The only machine I have that could do these parts is this 60Ton Boy
The parts would have to be done in modules that snap together, to do it in one piece you would need a 250Ton machine

[Deviant]

I'm a complete newb when it comes to injection molding.

Can you clarify why the tonnage of the machine matters? I thought that was the clamping force, or the injection force of the plastic.

I thought that work envelope and shot size was the deciding factor on what could be made. ((Obviously a complicated mold would have to fit in the machine))

It's possible that the frames could be made to snap together, but they would have to be glued or strong enough handle prying.

What about something like this?

[mactec54]

Deviant

How many ton the machine & shot size determine your part size most of the time, you need 3 to 5 ton per square inch, per surface area of molded part, to hold the mold closed

So your part you want made would be 80x162 is that the total size 80mm wide total 162mm total length

[307startup]

Seems to me you're overcomplicating the design and process.

There are a number of companies that make polypropylene honeycomb...it's used in various composite panels for the construction trades (think lightweight panels for high-end architectural apps, cube-farms and boat hulls).

Why not buy some off-the-shelf PP extrusions for a snap-together frame and capture the off-the-shelf honeycomb with that?

Might not be as cheap as $2/panel, but you can get 4x8 and 5x10 sheets of the PP honeycomb from many different vendors, and I wouldn't be suprised if you couldn't do the same with PP extrusions.

Examples:
http://nida-core.com/english/nidaprod_honey_h8pp.htm

http://www.ace-extrusions.com/extrud...-profiles.html

I'm guessing that you're trying to replicate something like this? : http://www.honeysupercell.com/

[diyengineer]

Deviant

The polyPro for injection molding is around $1 a pound for the resin

The only machine I have that could do these parts is this 60Ton Boy
The parts would have to be done in modules that snap together, to do it in one piece you would need a 250Ton machine

Silly question Mac. Why the need for so much force? I thought it was as simple as squirting some liquid plastic into a mold cavity?

I think its really cool, just my knowledge of injection molding is really really REALLY low. haha. Quick explanation would set me on the right path. Thanks Mac

[Deviant]

honeysupercell and permacomb are two options that currently exist, but there is room for improvement in their designs.

As for off the shelf, I don't follow. These measurements are pretty set in stone. The cell size for comb is very exact.

i.e. The difference between 5.4mm and 6.0mm honeycomb cell determines if the bee is going to be a drone or a worker. 4.8-5.4mm is roughly the range or worker cells with the current fad/movement toward 4.9 small cell bees for combating varroa mites.

Additionally, the various equipment requires the same external dimensions. ((Uncappers, extractors, etc..))

Seems to me you're overcomplicating the design and process.

There are a number of companies that make polypropylene honeycomb...it's used in various composite panels for the construction trades (think lightweight panels for high-end architectural apps, cube-farms and boat hulls).

Why not buy some off-the-shelf PP extrusions for a snap-together frame and capture the off-the-shelf honeycomb with that?

Might not be as cheap as $2/panel, but you can get 4x8 and 5x10 sheets of the PP honeycomb from many different vendors, and I wouldn't be suprised if you couldn't do the same with PP extrusions.

Examples:
Nida-Core Structure Honeycomb Core - Composite Material - Lightweight, High Strength Thermoplastic Honecyomb

Extruded Plastic Profiles - ACE Extrusions

I'm guessing that you're trying to replicate something like this? : HoneySuperCell

[mactec54]

diyengineer
Why the need for so much force? I thought it was as simple as squirting some liquid plastic into a mold cavity?

I think it would be nice if it was that easy, Think of the mold surface area as a hydraulic piston being pushed by high pressure pump, the bigger the piston surface area, the more it takes to stop it moving, in this case pushing open the mold, so you need 3/5 ton (sometimes more) Per square Inch of the mold surface area to hold it shut

[keebler303]

diyengineer
Why the need for so much force? I thought it was as simple as squirting some liquid plastic into a mold cavity?

I think it would be nice if it was that easy, Think of the mold surface area as a hydraulic piston being pushed by high pressure pump, the bigger the piston surface area, the more it takes to stop it moving, in this case pushing open the mold, so you need 3/5 ton (sometimes more) Per square Inch of the mold surface area to hold it shut

Mactec is correct, I will add to this further: The plastic resin is NOT like water and it has to be injected at very high pressures in able to fill the mold. Pushing the thick resin through small features requires a lot of push. To keep the mold closed you have to have at least as much force keeping it closed as the force generated by the high pressure resin trying to push it open.

So the high tonnage holds the mold closed really well so you can push the resin in really hard so you can fill your parts completely. It also has to be done quickly or the plastic will cool before the part is full.

Matt

[diyengineer]

Mactec is correct, I will add to this further: The plastic resin is NOT like water and it has to be injected at very high pressures in able to fill the mold. Pushing the thick resin through small features requires a lot of push. To keep the mold closed you have to have at least as much force keeping it closed as the force generated by the high pressure resin trying to push it open.

So the high tonnage holds the mold closed really well so you can push the resin in really hard so you can fill your parts completely. It also has to be done quickly or the plastic will cool before the part is full.

Matt

OOOOOOOOO. :idea:

haha!

That makes complete sense now. how much do those machines cost on average for a used older midrange model, ballpark? Every person in china must have hundreds of those suckers to deliver so much plastic stuff to america haha. I need me one

[mactec54]

diyengineer

You would be in for a big surprise at the price, most small used are worn out & not worth looking at,(there are lots on Ebay,Most are worn & sometimes only good for parts, You will have to spend the money to get a good computer controlled machine, You have to know what you are buying

The one in the photo start at $80,000 new, If you get lucky you may find one at $25 to $35 thousand used, Then you need a material dryer, a mold heater/chiller & the 3 phase power to drive everything, The list goes on

[RomanLini]

One of my favourite internet geniuses Ken Maxon has a very impressive home made CNC injection molding machine, it's on his page here;
Home Injection Molding
(there are hundreds of photos of it)

He makes robots using CNC too, it's well worth a look around his web page. Maybe he has a profile on this forum too, but I would not know his username if he has one.

[BVCFinancial]

diyengineer

Instead of going through the burden of laying down, $80k much less $30k for your new machines you could lease the machine through our company. This way you get all the benefits of a new machine at affordable monthly payments that we tailor to your budget. Contact us at BVC | Financial | California, we would love to help.

[mactec54]

RomanLini

Yes that's a great build, He does some cool stuff, That machine has been around for a long time

http://www.users.qwest.net/~kmaxon/p...mold03_137.htm

[diyengineer]

diyengineer

Instead of going through the burden of laying down, $80k much less $30k for your new machines you could lease the machine through our company. This way you get all the benefits of a new machine at affordable monthly payments that we tailor to your budget. Contact us at BVC | Financial | California, we would love to help.

lol. I would love to be in such a financial position to do that, but i am not.

[mactec54]

BVCFinancial
BVC | Financial | California, we would love to help.

I bet you would, If you can't pay for it, You don't buy it, Anyone that take's out a fleece is just plain Stupid

[diyengineer]

I bet you would, If you can't pay for it, You don't buy it, Anyone that take's out a fleece is just plain Stupid

Agree 100%.