Inventables Community Forum

Candy Bars!?

Everyone always asks me how I carve chocolate on my CNC machine. Its probably possible but it sounds very messy.

These are all soft maple carved with a 1/32" 2 flute up cut end mill at 40ipm on dewalt speed +/- 4

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This awesome, great work

pretty sweet gig you got going on there

Was so hoping they really were chocolate!!!

Great stuff!!

Very very cool! I noticed the little holes in your patterns, assuming they are for proper vacuum molding, do you pre determine their locations or do you attempt to vaccum then find out where you need them?

@TonyGutierrez

Pre determine. Once you fail at it for awhile you start to figure out where the mold needs to “breath”. Refer to the image below:

The GREEN arrows point to locations that are tight corners or places where the hot plastic has a hard time sitting flush with the mold positive. I basically think that the air will travel the place of least resistance first, so places like these (green arrows) I like to give a little extra suction power to help the plastic remove the air in that void. After a while I realized that the plastic will never actually sit flush to the bottom of the mold positive (except on large faces such as the border and the areas to the left and the right to the circle below). If you look at the pictures above of the molds, you may notice that you cant really see the holes in the positive. Thats because 90%+ of all right angles finish with small fillets.

The RED arrows indicate spots where there needs to be suction because the hot plastic will “plug” air flow. For example the letter “O”. The air in the inside of the letter has nowhere to go. The relief hole allows air to escape from these voids. I know that plastic will never reach the bottom of the void, but as long as it establishes a hard edge im happy.

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Awesome, thank you so much for the break down. I will definitely be trying this - finally a good excuse to build a vacuum table.

So, is it safe to assume that you drill the hole with the xcarve ( since they’re pre determined)?

I actually drill those by hand. I may have misunderstood your original question. What I meant by pre-determined was that I know where the holes are going to be long before the carve is finished.

With that being said, I have ruined a couple wooden positives by ramming the chuck of the drill into a small delicate letter or something like that. So be careful haha

2 Likes

You got it right.

Thanks again!

Very cool, nice work. Can you elaborate on your vacuum set up? Did you build it yourself? How do you heat the plastic?

I’m interested in using a similar technique fro light weight model airplane / car bodies. Thanks for sharing!

Google DIY Vacuum molding you’ll find plenty of diy vacuum molds and how it’s done.

@SteveBohlman

This Is my vacuum machine. I do not know who manufactures it. I have looked for identifying markings and have found none. The heating elements are electric charcoal starters for barbecues. They are around $15 USD at Ace Hardware. I built an adjustable frame to raise and lower the heating elements to my desired locations. I use a screw to pin it in place.

I dont have a picture of the frame I use at this very moment. I will take a photo later when I get home. In the mean time Here is a CAD rendering I whipped up.

The little “F” shaped extrusions shown in the picture below are how the frame is held in place on the machine. It uses gravity to pinch itself in order to stay in place.

Here is an exploded view of how I load my plastic into the frame.

You sandwich all the pieces together with these little black binder clips. I use like 4-5 for each side of the frame.

Great work and awesome results from a vacuum former! I do a lot of detailed custom chocolates for sweet 16’s, bar mitzvahs, weddings, etc of 3D scans I do of people, then I 3d print them and mold them. If you want to get all the detail without having any issues you’re coming across with the vacuum table, the best way to do it is mold it with a food safe silicone instead. Below are some chocolates I did of me as demos. If you need any links to the silicones I use feel free to ask.

B.

@EliottBrown Interesting set up. thanks for the info i hadn’t thought about using grill starters like that! I was thinking of just using a heat gun but don’t think I would get even enough heat. What would you say the largest Z deformation in the .025" plastic you have created is?

Those bars are like .5" tall and those are my most commonly formed pieces. I have formed some 1" pieces as well. I am sorry but I have no experience forming larger objects. I learned that Draft Angle is important so beware of overhang. I could be wrong, but I predict a vacuum former that does RC Car bodies the same size of my traxxas stampede, to be a rather large one.

-Eliott

lol

@EliottBrown yeah I’m having the same thought regarding size. I would need to build a large setup. Got to day dream right?

This is way cool. I am interested in the silicone. For me, I do 100+ bar orders, so Vac formed molds is the quickest and most cost effective way to get my bars/hr to a profitable level. At least with my current knowledge of molds in general. Dont you have to make your silicone mold in a vacuum chamber to eliminate air bubbles?

I would be interested in hearing about your scanner if you didnt mind sharing some information on that. Some skateboard trucks that we had scanned a couple months ago resulted in a model with so many polygons that solidworks freaked out and wouldnt load it as a solid. It would only load as a .stl image file? non-solid-body. My co-worker ended up using the stl as a guide and created a solid-body using surface modeling.

Cheers,
Eliott

My personal opinion is that it is very important to day dream. I would maybe think about making a shallow large box out of .75" MDF with silicone inside all joints. I tried making a box this way paired with a shop-vac and had below average results. I would get a hold of a vacuum pump. Harbor freight sells them im pretty sure.

Hi @EliottBrown,

The food safe silicone I use doesn’t require a vacuum chamber because of it’s low velocity. I’ve tried many and find this product the best IMO, It’s called Copyflex here is the Link. The nice part is they sell in small quantities so it’s not laying around. Your way is probably cheaper if you can get the details your molds need to be, for my chocolates there is a ton of detail and i’m sure your’s will also as you continue to grow.

As far as my scanner, it’s been a labor of love over the past two years, I’ve been meaning to kickstart the project but haven’t had time to focus on that part of it, I started setting up a website and facebook and instagram pages that has all the details about it. Hopefully i’ll get the Kickstarter going next month or so. Follow along…

Brian