[hpghost]

hi guys,

I need advises on MDF cutting!

I have an home made CNC with a Kress 1050 mill and 10mm diam 2 fluttes cutter.

I was cutting MDF at 5mm depth and 1000mm/min feed.

the Kress 1050 was at 3/6 speed (ie 12000rpm I beleive).

It is cutting with so much noize and the kress charbons finally burnt after 8hrs.

I saw that the glow inside the kress was important means that the motor was pushing too much but felt it would survive...

i tried slower feed, then the MDF was burning and I also tried increase Kress rpm and same result.

are the passes too DEEP for this machine? feed too high? or RPM pb?

please help...usually no issues with other materials even aluminium but MDF seems different!

thanks in advance for your replies guys!

[sandiegocadcam]

From my personal experience with cutting MDF, I have found that using slower rpm's is the ticket. You won't get much dust and your tools will last longer since that edges are not "rubbing" the material. Try to use a down cut spiral mill if possible. I have used this method numerous times while I was making bucks for thermal forming.

[hpghost]

is the other settings ok? the problem is that with the lower rpm the Kress was getting too hot which I beleive means that it was asked for more torque than normal one.

I am afraid that lowering torque might not be enough...don t you think so?

[sandiegocadcam]

what is your depth of cut? that is the key. if you are doing full, tool width cuts, simply back off the depth. if your software allows for cases when using full tool diameter cuts, try a trochadial method of cutting when the tool engages full width cuts.

[hpghost]

as mentioned, the depth is 5mm.
the first cut is of course plain diameter in the material then from 2nd onwards it is 50% diam tool.

the cut method is opposite

[sandiegocadcam]

my apologies. i forgot you post the feeds. i am not familiar with the type of spindle you are using, but to me, it simply sounds like that is a very weak spindle. 5mm is not deep at all. i have a small K2 i just purchased just to see how things tick with a small machine and i loaded a dremel tool on it and was plowing thru .750 plywood with an 1/8 endmill.

[hpghost]

I use this:
http://www.kress-elektrik.de/en/prod...ct.php?id=3319

in fact this is honestly a good tool...in ply I can cut 1cm deep with the same setting...

[sandiegocadcam]

i cant see anything wrong then. my gut feeling is leaning back to the spindle itself. how are you holding a 10mm bit in a spindle that is made for a 8mm max size? i know it can be done, but if you look at the technical data, that milling head is only rated for 8mm.

[tahustvedt]

i cant see anything wrong then. my gut feeling is leaning back to the spindle itself. how are you holding a 10mm bit in a spindle that is made for a 8mm max size? i know it can be done, but if you look at the technical data, that milling head is only rated for 8mm.

Kress can supply collets from 1 mm up to 10 mm i believe.

[sandiegocadcam]

the below is what i found in the tech sheet listed for his router:



8 mm clamping jaw
Art. No. 91482001

for OF 6990 E, FM 6990 E, FM 6955, 1050 FME, 800 FME, 530 FME

[hpghost]

you are right guys the standard is 8mmm but thanks god there are some guys producing other collets:

http://cnc-plus.de/index.php?cat=c10...-und-ISEL.html

this is also why I like this tool.. have 8mm, 1/4", 1/6" and 10mm with me so I can use a lots of differents cutters!

[sandiegocadcam]

that actually sounds pretty cool. i have a 892 PC now with only two collets. i might look at changing over to the Kress if you get your issue figured out.

[hpghost]

except the mdf cutting it is perfect tool

[hpghost]

actually, an other cool feature is th constant RPM thanks to speed regualtor so even if torque is increasing the rpm remains

[Oldmanandhistoy]

Hi all,

If you want faster feeds use STC up spirals; cutting forces are greatly reduced. I use up spirals as it clears chips better than down spirals but if a good finish is needed to the top surface or I want to cut thin material I use down spiral (helps keep the timber on the table especially if you are using vacuum clamping).

I would recommend the Kress router as imo it is top quality, I have three of them.

John