[redou]

Hi folks,
I want to buy a chinese CNC machine those listed on ebay. The 6040 suits my future project but the shipping to my country is too high + the machine could be held for customs. Now I am wondering if a smaller machine (the 3020 for example) could be upgraded to a 6040 by just buying or manufacturing the frame. Apparently the electronic boards are the same and there are no limit switch.
Best regards.

[RunForrestRun]

Yes it's possible. You could reuse the z-axis assembly, the stepper motors and the controller. But if you can build a new frame you could probably make the z-axis yourself too.

[redou]

Thank you very much "RunForrestRun" for the precious answer.
Just for the sake of information the machine previously mentioned does contain a limit switch.

[awerby]

It might be better to just buy the larger frame, without the electronics. Most of the problems we hear about from owners of these things relate to the poor quality of the supplied drivers and associated electronic parts. If you put together your own set of motors, drivers, breakout board, power supply, etc. you could be better off (especially if you bought good ones, and not the cheapest things you found on ebay...)

[redou]

Thank you for the advice "awerby". The biggest problem I have is concerning the customs. If they see something big, industrial or unusual it will be confiscated and there is no need to pay for customs because your item is lost forever. I'll start with something small such as the 3020 at my own risk (I hope it will be received).
As mentioned before, I thought about modifying the 3020 but in order to do so I need a ballscrews which they are not found in the local market. This has lead me to think about galet-belt transmission. How the conversion is made? I mean how should I choose the correct galet and belt dimension?

[awerby]

People who steal things usually want something that works (or at least appears to) so they can sell it to someone. If you're importing an item that's not immediately useful, chances are greater that it won't be stolen. If you got the machine in kit form, so it required assembly as well as a control system, it would cost less to ship and also be less likely to disappear on route.

What's a "galet"?

[redou]

It’s a good idea to buy the CNC in a kit. In fact, they ship the 3020 in a semi-assembly (only the frame is assembled). However, from where I come from you can expect the unexpected and even the unstolen (not working things) are confiscated . Last time I tried to send a non-functional hard drive customs agent accused me of being a national security threat.
In case I try to buy the CNC in parts the shipping cost will be added to every part. Just immagine the total price of all parts using Fedex. The shipping cost is cheaper when things are combined.
I used the word 'Galet' in french sorry. I meant, a roller or a pulley and a belt.

[RunForrestRun]

Yes I packed my 3040 machine in a suitcase to bring it on a plane for similar reasons. I wouldn't like to try it with a 6040 machine though.

You can buy ball-screws and most of anything else you will need on AliExpress or eBay. I recently replaced the bearings with a set I got from eBay for $6. Now that I think about it, maybe it was the plane journey that damaged them?

[RunForrestRun]

I don't bother with FedEx. It costs a lot and then they add it on to the cost of the parts and you have to pay custom duty of up to 100% on the total. I can get smaller items through regular post and they don't charge and duty. 95% of the time I get what I ordered but I guess it depends on your local post office.

[redou]

It is a nice idea 'RunForrestRun' to travel with your CNC but traveling just to buy a CNC is a crazy costly solution.
Today I checked with many seller I and was amazed. Most of them do not ship to my country, others they offer a very high shipping sometime it is the price of the machine or more.
There is no way, I'll not use the regular post. I lost even tracked items with this method. (in case you lose an item you need ti fill a claim -you pay off course for this procedure- and you wait for 6months or so. no guarrantee for an answer)

I still wonder how to transform the motion from a ballscrew to a roller transmission?! is there any calculation, if so, what is the formula? is transmission with a roller reliable? does it have any disadvantage?......