Retrofit or not retrofit, that is the question

Hi there!

We have a small shop, and we have a very new project that we need to buy a few robot arms to welding and some milling tasks.

We are thinking seriosly to buy a LinuxCNC compatible arm or cnc station and we need to choose some of them. We already don't know which is the best bet. 

Options for us using LinuxCNC:
1. Buy a second -or third- hand arm/machine and retrofit it?
2. Buy a new machine or parts and make a completely new system?

Specs for ther the robot arm: Any Like fanuc with 0.02 repeatibiilty and 35kg of payload for example.

Thanks in advance for your help.

P.S.: Sorry for my -for sure incomplete- first post. 

1 and 2 .... (repeatibility is not a problem) ....

every new project depends of money you would spend, or you would make. If project if for your usage, time spend on can justify a retrofit based on Lcnc. If project is for sell to a customer .... not sure .... probabily depends from local economy.

After these "inventor" have a cam for Lcnc not sure for robots .... plus for welding there are a lot of ready made cadcam or native gcode generator software .... from 3800usd to really more .... at lower mentioned price is quite simple create a xml table for run your robot Lcnc and have a code generator too. Best commercial software can not uses with Lcnc .... BUT welding is a long work to do and more difficult than mill or late .... so keep in mind: what is my level of knowelge of linuxcnc? how my level on fanuc robot? how my level on xxxx brand of plc?

For complex project is real better work on what is really well know ..... on these way you not add complexity to your project .....

After these .... Lcnc on robot can be used but have not all required features for modern robot working .... like limited area working, safety area control, and pause/stop on max extension of arm .....

You can for example using linuxcnc for retroit milling for sure, good example, .... welding robots ... better make some milling retrofit before to retrofit robots.

but take my worlds like a friends of pub opinion ....

regards