Felder Panel Saw K700s "curved" cuts problem???

[Goldcrest]

Dear Members

I have a problem with almost new Felder K700s Panel Saw. When cutting long mdf boards ( ply also )
saw seems to make a curved cut. When you touch both cutted edges together it appears that there is
a 1.12mm gap ( + - ) in the middle but start and end of the board are true for approx 100mm - then the
gap starts to be visible.

It happens on sliding table side and ripcut fence.

If you turn one piece upside down and touch cutted edges together then it appears that middle is touching
eachother and on ends gaps starts to be visible.

Felder send already two service guys ( one is still trying to find what's going on as I'm writing ) and it seems
they giving up. To be honest I'm also in dark what can cause this problem.

In attached photo you can see gap in the middle.

Anyone had this situation before? Maybe on other machines?

Any help highly appreciated as we are doing 2500-3000m high doors for wardrobes and with this issue we just
cannot proceed with orders.

 

[Chrispy]

I've allways put this down to the wood springing when cut, as often both pieces bow in opposite directions.
I just cut oversize straighten and recut to finished dimentions, a bit of a pain but works for me.
by the way my saw is a older Wadkin.

 

[flh801978]

Have you measured from your reference side to the cut side does the cut vary in size along the cut ?

(this is just to see if it is internal stresses being released)

 

[clivethecarpenter]

This problem used to drive me round the twist ripping full length mfc / mdf boards
Its caused by tension in the board unloading when its cut
The trick is to trim the board twice once to relieve the tension and then second cut to size up
That or your saw is out of set !

hope this helps

 

[custard]

The fact that you're getting exactly the same problem from both the cross cut table and from the fence does suggest it's a materials issue rather than a saw issue. But I'm puzzled that you're having the problem with ply and mdf.

Has this problem just started, or is the saw new and it's been like this from the beginning?

Incidentally, the Felder Owner's Group on Yahoo is a great resource...David Best, the guru of all things Felder, is a regular visitor.

 

[ProShop]

FWIW check to see if the blade is doing a back cut, if it is the trunnion is out of alignment. I had this with my Felder.

 

[clivethecarpenter]

Did you find the problem ?

 

[Bradshaw Joinery]

Yes material tension I think

Like said, check the piece that was fence side to see if its parallel, but no saw setting would allow the saw to cut more out of the middle than the ends or visa versa, without the blade wobbling or material being run in parallel to the blade.

 

[Bradshaw Joinery]

You can check this by accurately measuring a piece of MDF before cutting at the ends and middle, then measure the two halves after the cut . If the offcuts are the same width along the length then its material tension issue as the saw is taking an equal cut. Also mark the faces of the material and the cut edges, so you can tell which way the bow is. IE is it doing a curved cut along the length, or are they springing together as they come off the saw?

 

[dohertycarpentry]

I'm having the exact same problem and it's driving insane.

 

[johnnyb]

I'm guessing the whole thing bows. if that s the case surely you would have to cut 3 times to get a true piece. Once to get the bow once on the bowed edge and then a rip to size? (if only my saw was as accurate as your felder!)

 

[peterleyton]

Just wondering if anyone still following that topic I have exactly same problem with my Format 4 kappa 40.