My Kuka CNC robot shakes when operating

Hello everybody,

I'm a CNC programmer with 5 years of experience in the field,

i've been operating both ABB robots a n KUKA machining both natural stones and soft materials like

timber, polyhurethane and poly.

A few months ago we bought this KR 270 R2700 ULTRA which shakes and rattle when axis 1 and 2 are in motion.

The only way to minimize this problem I found, was to reduce the speed down to 1250 mm/min, which is very slow and not ideal for some operations and materials.

It happens both in T1 and automatic mode.

I believe it is not a mechanical issue but of course I might be wrong...

the robot is a refurbished one.

Could you help me get an idea of what the problem/s might be?

Many thanks

Best

Daniele

Quote from panic mode

well you did not provide much really. does this happen at this speed with or without tool contacting product?

21mm/sec while cutting how thick slab of what material? what is estimated load? what is the weight of the tooling? how is tooling mounted? what are typical A1/A2 angles when this happens? is the robot near one of singularities? is robot properly anchored to a KUKA recommended foundation? is the tooling attached securely? how far from center of the wrist is the blade edge that contacts material? is load entered correctly? is elasticity compensation deactivated?

Hello Panic Mode, thanks for you reply.

I'm mainly cutting very soft materials like polystyrene or 150kg/m3 polyhurethane foam, but the issue is of course not related to cutting since it happens with manual movements as well, so with no load on the arm (only the spindle). I use a simulator that avoids all sigularities for me, and the whole hardware has been provided by a renowned company so it is all properly assembled ad bolted down (hopefully!). I generally machine in the following position: A1=7 A2=-51 A3=86 A4=-1.43 A5=60 A6=-260. I was recommended to use the external axis as a way to reduce the use of the first and second axis, but accuracy worsen and the issue is still there!

" is load entered correctly? " Not sure what that is, but i guess it should have been set by the provider

"is elasticity compensation deactivated?" Not sure about that either...

It looks to me like there is some conflict between speed and acceleration, something that gives a bad feedback...

The provider has been a bit evasive on the issue, so my reason to be here is to be able to pin point the problem and get it sorted by him!

Really appreciate your help

it really is precious!

Many thanks

Dan

Many, many thanks Panic Mode for your time in answering me.

I've got one more question: is there a manual or a document I can get my hands on to understand a bit better the variables you listed above?

Many thanks again,

Dan