[ardenum2]

Looks like a good choice going to 4mm dia. on the pins, the middle of the pin should press onto the horizontal edge of the guide, otherwise if too small it would pry the thing upwards instead.

Got your chiller yet? fox looked some time ago what's inside his and it was just an aluminium pipe, which is much less efficient than pc watercooling radiators with fins. I can't see how such a setup would be better than a diy pc style cooling, maybe your radiator was just too small?

[badhabit]

Looks like a good choice going to 4mm dia. on the pins, the middle of the pin should press onto the horizontal edge of the guide, otherwise if too small it would pry the thing upwards instead.

Just make sure that your railtrucks have clearance to the bolts. There is only 0,5mm on my setup with 4mm pins and the bolts i've chosen. Again, i'd advise to make a test-setup to see if everything works out. The 3mm also presses against the horizontal edge, but the bolts went a bit to far into the threads in the mounting surface for my liking... i could have countersunk the threads a couple of milimeters aswell, but i chose to use 4mm pins instead since the rail trucks seem to pass just fine with 0,5mm clearance...

Got your chiller yet? fox looked some time ago what's inside his and it was just an aluminium pipe, which is much less efficient than pc watercooling radiators with fins. I can't see how such a setup would be better than a diy pc style cooling, maybe your radiator was just too small?

I'm not sure what sort of "chiller" fox bought, but it seems to just be a passive one? Which isn't really a chiller, more just a "radiator, pump and reservoir in a box"... I bought an active one with a compressor and "real" temperature control. You can see the compressor in the middle:

This enables me to have my components at a fixed temperature, nomatter the temperatur in the room. With fox' "chiller" or with pc watercooling components i would never be able to maintain a specific temperatur(say 20c) at all times, at best i could get a couple of degrees above roomtemp, never a fixed temperature.

[ardenum2]

Attachment 488970
This enables me to have my components at a fixed temperature, nomatter the temperatur in the room. With fox' "chiller" or with pc watercooling components i would never be able to maintain a specific temperatur(say 20c) at all times, at best i could get a couple of degrees above roomtemp, never a fixed temperature.

This definitely looks like the real deal. Vevor seems like it has some good selection of equipment these days.

[ardenum2]

hey badhabit, what kind of bags does silimix come in? Is it dry or did you have to dry it before mixing?

[badhabit]

hey badhabit, what kind of bags does silimix come in? Is it dry or did you have to dry it before mixing?

It was in 25kg bags and it was very dry (and dusty!!).... remember to use a respirator when handling it, you don't want that fine quartz dust in your lungs...

[ardenum2]

It was in 25kg bags and it was very dry (and dusty!!).... remember to use a respirator when handling it, you don't want that fine quartz dust in your lungs...

well this solves that problem than, drying 300kg of this would not have been a pleasant experience, thanks

[suspension]

Bottom mould is completly assembled now. All bare or sawn edges are taped of with releasetape and the mould is ready for a coat of releasefilm before mounting all the anchors:

I was in doubt how i should seal these ends, but ended using the tape. I did consider painting the ends and then wax them, but almost nomatter what i do, there will always be some sort of impression in the EG, either from the wood structure or from the tape. With the tape i at least know it will release very easy...and most of the casting will be covered anyways:-)

I originally added ribbing on the underside of the mould to help support the mould and to somewhat isolate it from the concrete floor during the curingprocess. However, i'm not sure it helps anything now that i've assembled it :-)


The top mould is fully assembled, but i didn't manage to finish up the top-mould with tape tonight...maybe tomorrow :-) This is how it looks now, currently upside-down:


(Before anyone asks, this is the tape i've used: https://www.easycomposites.co.uk/flash-release-tape I've used it previously and it's nice to work with, sticks pretty good while still removeable and nothing sticks to the top side of the tape...)

Could I know how you designed these moulds? I mean did you use some facility in your cad package or did you designed them manually based on the shape of the column/base?
For my DIY CNC, I designed a mould using CAD, but that mouls os of course a solid mould and need to be machined (impossible). Rather, what I need is a mould that can be made from say MDF sheets. How do I do that?

[peteeng]

Hi Sus - You design the parts as you want/need, then you build the mould around those parts associating the mould sides back to the part sides. In this way if the part changes so does the mould. Peter

[suspension]

but that does not create a design for a mould that can be solidly put together as the case for this design.

[peteeng]

Hi Sus - You still have to add the webs and tabs and slots to all the parts and since these will be associated to the mould sides they will change if the part changes as well. If your asking if there is an automatic way to do this there isn't... Peter

[suspension]

Hi Sus - You still have to add the webs and tabs and slots to all the parts and since these will be associated to the mould sides they will change if the part changes as well. If your asking if there is an automatic way to do this there isn't... Peter

would it be possible for you to post a link for a video which shows this process? (may be in fusion360).

[peteeng]

Hi Sus - Its easy in F360 as its a top down modeller. You build your main component say the column, then you build the sides of the mould on that column as components related to the column sides. Create the mould as a sub component so you can extract or draw it easily. If you can create assemblies in fusion then you can create the mould. Imagine a cube as a component then build 6 panels around that cube related to and using the cubes edges. Then add webs and extras. Then add tabs and other details. No videos have a go. Peter

I've attached an image. The pink component I have called gantry, then I built component 2 off of one of the sides. C2 is now related to the gantry and if the gantry changes so does C2. C2 is the mould side... So now you can add webs, extend edges and chamfer, add tabs and holes etc etc. Keep at it. Peter

I added some more components to the model in "mould" they are all related to the base geometry so change the "gantry" and the mould changes with it... The panels are 17mm plywood.

I made a column with a angle in it. I then made the panels off those sides , then "cut" the mitre for those panels. Now if the mitre angle changes the panels will change. I'm sure you can figure this out. Peter

[ardenum2]

would it be possible for you to post a link for a video which shows this process? (may be in fusion360).

there is no secret to this, you just have to do it and then refine it 10 times and you get what badhabit ended up with. If the mold gives you this much trouble I have a bad feeling about your main parts then. It would be wise to put a hold on casting, take a week break than come back, then take a break then come back etc. do this a couple of times and usually by the nth time you notice something is wrong. Also badhabit has a big router so his mold was designed with that ability in mind.

I've seen your bed, it's unnecessarily complicated, especially the middle part, I see walls too thin there too, what are all these holes for? it doesn't have to be this much complicated, there's plenty of things to change to make your life easier eg. the side angles are not necessary you can achieve the same "chip evacuation" with sheet metal after the casting. The mounting plates for the column are up in the air, no support there, also separate them from linear guide plates, make sure no metal parts touch each other, cold casting is all about isolating structural components from one another so that the only thing that connects them is the main cast body. Chamfers or fillets are only necessary for uhpc/grout and in that case all the sharp edges must be chamfered/filleted. This doesn't impact the shape of your mold, you achieve this by simply smearing silicone on all the inner edges.

What are you casting with?

How are you going to make the saddle? stefs or badhabits saddle is a beautiful piece of fabrication, this is much harder to make right than a mold. Maybe consider having it premachined from a solid block?

why a C frame?

[suspension]

Thanks @peteeng for the tips. I will try this out.

@ardenum2 Actually, I just wanted to replicate a scaled down design of stef's and badhabits. Since this is my first DIY build, I am sure there is lot to learn from their designs and I hoped that the specific design with holes, chamefers, etc had some reasonings behind. Same goes to C section. On top of that this looks nicer than a pure box design. I had provisions to make it simpler if I cannot make a good mould to cast it, but before that wanted to give it a try. I have access to CNC router workshops, so as long as I can get CAD drawings of mould's parts, this should be fine.

Regarding saddle, I have not decided yet. I guess I will try to follow similar design to Stef (maybe use scale up/down functionality of Fusion) and get the pieces laser/plasma cut through a workshop. Welding will have to be outsourced too.

[suspension]

I did some simplifications in the base. Willing to do more if needed. Please refer to that thread for more details. I do not want to change the main topic of this thread.
BTW, I am planning to cast with epoxy + gravel + sand.

[Mr-MaW]

V8 series vertical machining center
High performance milling performance.
The machine bed, column and other basic components are made of German high-performance mineral castings. Compared with the traditional high energy consumption iron castings, they have excellent vibration absorption, thermal stability, high rigidity and corrosion resistance. At the same time, the room temperature curing internal stress is small, green and pollution-free, energy saving and environmental protection.
By FEA analysis and pyramidal pattern deign,machine bed gain the optimal structural rigidity,the static rigidity is improved by 57%.

https://grabcad.com/library/mineral-...ning-centers-1

If you need mineral castings.You can contact me,I'm from China,My company has produced a lot of products, small can reach 100KG, large can do 46 tons.Linear motors。

[badhabit]

there is no secret to this, you just have to do it and then refine it 10 times and you get what badhabit ended up with. If the mold gives you this much trouble I have a bad feeling about your main parts then. It would be wise to put a hold on casting, take a week break than come back, then take a break then come back etc. do this a couple of times and usually by the nth time you notice something is wrong. Also badhabit has a big router so his mold was designed with that ability in mind.

I've seen your bed, it's unnecessarily complicated, especially the middle part, I see walls too thin there too, what are all these holes for? it doesn't have to be this much complicated, there's plenty of things to change to make your life easier eg. the side angles are not necessary you can achieve the same "chip evacuation" with sheet metal after the casting. The mounting plates for the column are up in the air, no support there, also separate them from linear guide plates, make sure no metal parts touch each other, cold casting is all about isolating structural components from one another so that the only thing that connects them is the main cast body. Chamfers or fillets are only necessary for uhpc/grout and in that case all the sharp edges must be chamfered/filleted. This doesn't impact the shape of your mold, you achieve this by simply smearing silicone on all the inner edges.

You are bang on in your advise to @suspension:-) It takes a huge amount of time to design the moulds, there is not easy fix for this. This will also continuesly simplify the design of casting, since you'll discover things that are very hard to mould(or get out of a mould!)...

But i thought it was an interesting and very fullfilling process to do. Almost nothing beats the feeling after taking the mould apart and seeing the casting for the first time.... "i made this"...

/Thomas

[badhabit]

Could I know how you designed these moulds? I mean did you use some facility in your cad package or did you designed them manually based on the shape of the column/base?
For my DIY CNC, I designed a mould using CAD, but that mouls os of course a solid mould and need to be machined (impossible). Rather, what I need is a mould that can be made from say MDF sheets. How do I do that?

I'm using Fusion360. I have each casting as their own component in their own file. I then created a new design for each of the moulds where i imported the casting into as . I then simply build up the mould around the casting just as it would lay on the floor during casting. So you casting has to be "mouldable", in my case i was using 9mm and 15mm phenolic plywood(would HIGHLY recommend, worked awesome!) so all measuremens on the mould in the vertical direction(during casting) had to be divisible by a combination of 15 and 9mm in order to stack the plywood. Consider the weight of the casting and account for the deflection in the wood due to gravity. This is why i have this grid on the back to support the plywood as much as possible. This was also why i made the steel structure below since the floor wasn't flat nor level.

The webbing, holes and so on are all done manually. The same with the "dogbone" cutouts for the webbing. There are tools for some of this, but i found it faster to just do it manually and then copy features/components around as needed...

Enjoy :-)

/Thomas

[Mr-MaW]

Unpacking the mold is very skillful, when you design 100 sets of molds and participate in disassembling the mold,You will summarize a lot of experience,The metal mold we used before broke the mineral casting. The price is very high, but failure is the mother of success.
So we make molds now quickly, because there is enough experience, and we can finish the mold making within 15 days.

[Mr-MaW]

Hi @peteeng and @badhabit ,

I don't know why but my Tapatalk does not send push notifications, so I'm missing replies.

My hobby room (cellar) is very small and I have limited space. Currently I have a cnc BF20L, a cnc SIEG C6, a 400x500mm router and various common tools. These dominates all the room. Believe me I don't even have the space for my toolbox car.

I want to build an eg mill to replace the BF20L however what @badhabit says is exactly what I meant. To make a small eg machine stiffer I can design and use a metal skeleton but then there will not much volume to fill with eg.

Best,
Suat

Sent from my MI 5s Plus using Tapatalk

Hello, friends from Turkey, nice to meet you.
If you fill the steel pipe with mineral castings.I don't think it's a good idea, there will be a lot of problems, because the materials are not the same, the two materials will be very constrained, affected by temperature changes, and become very unstable.
If you don't have special materials, you'll just make the device heavier, not harder.

So I recommend that you use mineral castings directly instead of filling the steel pipe with mineral castings or UHPC.
And there are many customers in Turkey who use mineral castings directly, because my customers export machining center milling machines to Turkey.I hope you can understand what I mean, directly use mineral castings instead of cast iron.