[denhen89]

(Short info about my CNC experience: 2017 i started with the CNC hobby and until today i have build 4 machines. A large and pretty precise 2500x1250mm CNC Router (able to cut steel with good perfomance), a CNC Lathe (conversion) which was a old Polish heavy industrial Lathe which now has linear guide rails (45mm and 25mm), servos, MESA 7i76e, MPG handwheels for both axis, and some other nice features. Also i have build a Co2 Laser cutter and engraving machine and a cnc painter)


Hello Guys,
i have actually only one generall question, but i will add some info why i am asking the question:


Do you think the DIY CNC community (especially Milling machine / Routers / Lathes) is getting bigger or smaller year after year?


I am asking that question, because i would like to start a side business, next to my main business, so i thought about building machine bases out of UHPC Concrete.


The Machine bases should be mainly for hobbyists (not only), but in highest possible quality and accuracy, especially of the important surfaces, e.g. for linear rails, ball screw bearing mounts, spindle mount. The customer who buys the machine base, doesnt need to think anymore about aligning the linear rails, which means no costs for precision tools like granite surface plate/straight edges and e.g. granite squares as well as no loss of time.
The important surfaces like for the rails should be in a tolerance of 0.01mm, which i know, its not easy to achieve (-permanetly, due to thermal expension and so on), but i would get it done and i already have good ideas how the production process could be.


I know from myself that buying a working machine in 2017 wasnt a solution - i wanted to build it myself and learn it. BUT, i spend over 2 month just for aligning the linear rails. (it was a pain for my large CNC Router).
I believe that building the machine is for the most people the most interesting part when it comes to CNC, and its not only about being able to mill out parts with strange shapes. Its the planning of the build, ordering parts, learning, optimizing and so on.


BUT, when i am honest to my self, then i have to say that i was extremly happy when i got my Lathe-bed back from the machine shop and could install the Z-rails without vertical and horizontal alighment. (i had a datum edge and perfectly flat surfaces). The Z axis and X axis plate i had milled on my CNC Router with a accuracy of 0.04mm, so it was pretty good, but i still had to spend a couple of days to align those rails and then also align the X axis to the Z axis.


I am sure that the most peope who start such project for the first time think that 0,01 mm is a nice number and thats what they try to achieve, because i know from my self how fixed i was to achieve 0.01. It took me really over 2 month to align my rails and at the end i still had a error of about 0.05 mm on the whole big cnc router, which of course is super nice, but i lost 2 month of my life . What i want to say is that i would never ever do it again.


For small machines its a different situation, but still you need precision tools (which are not cheap), mostly even after the surfaces where machined. (take a look at videos from ALEX CNC, who build a UHPC VMC - after machining on a super modern high end machine he had a error of over 0.10mm if i remember correctly and then he had to buy precision tools and scrape the surfaces)


Okay, enough of trying to explain how i got the idea of building machine bases and the psychological part of DIY CNCs - now the most important part: The Price of the machine base
(I didnt mention what size the machine base has to be, but as example take a look at ALEXCNC UHPC VMC milling machine on YouTube)


The price should be that low that someone who wants to build such machine will think 2 or 3 times if he really wants to spend money on the material for the machine base, building the machine base, machining the surfaces, spending money for precision tools and spending days or weeks to align the whole machine, INSTEAD of just buying a ready machine base, where you just order the correct rails, ball screw and ball screw mounts, install it and the geometry is DONE within lets say 1-2 hours.
Of course the price should be fair for both sides, so that it makes sense for me to build that machines, but as i wrote earlier, its should be a side business, so if i manage to build 2-5 machine bases in a month it will be fine for me.


I havent done any calculations, but i am trying to imagine i want to build such VMC machine as the one from ALEXCNC. I can imagine that when building such machine for the first time and you have no machines available and no precision tools, you would spend at least 1500-2000 € just for the material for the base + the precision tools like straight edge/granite plate, angle square. What you cant forget is that you also have to spend time on drawing/planning the build and depending on the main material of the machine base, you might need a welding machine for a welded base, or a Concrete mixer for a UHPC base, or a mixer and a vibrator (not the one you are now thinking about) for a Epoxy-Granite base. Also you need to build the casting and buy special release agent.
There are many things that will add up slowly and i believe that many DIY CNC builders would decide for a ready machine base if the size and type fits their needs.
In my case, i would really decide for the ready machine base and be happy that i have the worst part behind me.


Now, please let me know your honest opinion on my idea and i would like to know what would you be ready to pay for such machine base (as example: like the one from ALEXCNC UHPC VMC build)?


Some side info that i forgot to mention:
I am from Germany/Poland, living in Poland and the market i would want to target is the EU-Market at the beginning.
ALEX CNC UHPC BUILD: https://www.youtube.com/watch?v=gvgB...hannel=AlexCNC


PS: Please remember, its for now just a idea that i have since a couple of days, so when it comes to the price, its really difficult, but if i will decide to start such business i will of course do precise calculations for a specific machine base that i will design and then it will be easy to tell the price.


Thanks in advance guys.

[awerby]

I think the shipping costs would make most prospective buyers think twice - or maybe 4 times.

[denhen89]

I think the shipping costs would make most prospective buyers think twice - or maybe 4 times.

Shipping costs are not really that high within the European Union. 120cm x 80 Euro-pallet is about 100,00 to 300,00 €, depending on the distance. We are talking just about the machine base and weights of about max 600 kg.
And the courier always has a pallet jack - for a small tip he will move the base to the location you want in your workshop

[peteeng]

Hi Den - A few things. To make any product viable you need volume. You need the machinery to make that volume and that product has to met the market expectations. I speak to a lot of people about machines and everyone wants one slightly different. I doubt you will be able to make just a base and make money. If however you make a machine (or at least the major parts as a set) then I expect you will get some sales. I spend time with people discussing their machine and many being "Makers/DIY/optimists" decide they will do it themselves "how hard can it be anyway " either to save money or to prove to themselves it can be done by themselves. Many fail or start then stop. It takes a lot of resources, time and determination to complete a machine. Good luck with the venture, think it through very carefully and keep us in the loop.... The video shows that you can be very careful and still have issues in the build... It only takes one problem to wipe your profits. And if you cast 3 or 5 bits then you definitely have blown your savings to fix multiple objects... Been there a few times... Peter

eg a 30min call with an enquiry this morning has been about a 1200mm wide machine now he has decided it needs to be 1500mm wide. If you had a std part you would lose the sale, if you try to make a bespoke part you won't make $$$.

[joeavaerage]

Hi,
I have often dreamed of doing something similar, but I would not be using EG nor granite nor UHPC, I would cast in grey iron.

Why use anything less? There is a very good reason the vast majority of the worlds machines are made in cast iron, its stiff, well damped and highly flexible with regards size and
shape.

The issue that peteeng raises is doubly troublesome here, you have patterns and flasks ready made....now someone wants an extra 100mm travel????....not going to happen.

You would really have to design, cast, heat treat and machine to size a design at such a cost that is so compelling that hobbyists might buy it. A very tall order. Most hobbyists shy like a
frightened horse when you mention price. Additionally, in my case, being in New Zealand, I know the shipping is going to be huge to go ANYWHERE....mind you it will always
be downhill to wherever....that's the good thing about being on top of the world, philosophically and morally speaking!!

Craig

[denhen89]

Hello guys,
sorry that it took so long to reply, but i had a lot of work to do, and about 20min ago i started to answer here, but then my pc had to be restarted, so the text is lost.
I will reply as short as possible.

So, you both had some good points, but it seems that you think the size of the machine might be the biggest problem as well as the price. Its really like that, that a hobbyist might not be ready to pay e.g. 2000$ for a machine base and decided to buy the material for that money as well as the precision tools needed to build a precise machine base by him/herself. When it comes to the size i think its not such a big problem, due to the fact that its not a huge problem to have lets say 2 sizes of a machine type, e.g. small/compact (e.g. like the one from ALEXCNC) and mid-size VMC.

I know that Iron is a very good material, but do build such machine bases you have to invest a lot more at the beginning and i also believe it makes only sense if you make a bigger order. In such a "side-business" i think UHPC/Epoxy-granite is a better. If would start such business, i would build the mold out of e.g. 10mm steel sheet metal. Welded together and reinforced from the outside with e.g. rectangular profiles. Once the mold is build. you just need to fill it and open it after e.g. 24 - 48h. Then you leave the machine base to dry for at least 2 weeks. I will not explain how i would continue in the production process, but i would NOT need to spend much time for building one machine base (i think max. 20-30h of direct work on one base), but it would still take about 1 - 1,5 month until the machine base can be shipped. This doesnt mean i can do only one base a month, because theoretically i could build about 2 bases a week, but even if i would manage to build only 1, it would be still enough, at least for the beginning more than enough.

Of course i also thought to build a complete machine with electronics, but then you have to follow a lot of rules, have some certificates, etc.. which would be not ideal as a side business. The reason i thought to build only machine bases is that its mayby not the most difficult part, but the most time consuming part for which you also need to buy special tools or machines and pay for labor work like machining. BUT, if you can buy a ready machine base, and you can download the CAD file of the base, it will save a lot of time for the person that wants to build his own precision machine.

I can of course understand why you are a bit pessimistic about the idea and as i wrote earlier you had both had some good points, but you can never build a product that is so universal that it fits everyone. I will continue to think about that idea, but it was good to get a feedback from you. Thanks for that

[joeavaerage]

Hi,

I know that Iron is a very good material, but do build such machine bases you have to invest a lot more at the beginning and i also believe it makes only sense if you make a bigger order.

Disagree. If you make a simple part it can be done with one pattern. Simple patterns are made in wood and vastly easier than to make than a mold.

When I had my axis beds cast I thought to make all three identical so only one pattern is required. The foundry has the services of a master craftsman pattern maker so I had him make the pattern. Cost $300NZD ($200USD)
for the pattern. The castings complete, ie the pattern making, molding, pouring and fettling cost $3300NZD ($2000USD) for three 115kg each castings.

If your design is careful you will need one or maybe two patterns, or rather a single split pattern. If you want sand cores that when the initial development of patterns and core prints go up.
The bottom line is that casting in iron has always been an economical industrial process. Do you suppose the approx 500 million tons (annually) of grey iron castings would be if they
were NOT economical?

Craig