OVAL OBLONG DRILL SLOT NC-ROUTE

 If I understand the question, it seems that you need to create a padstack and select Oval Slot for the hole type.
Menu > Tools > Padstack > Modify Library Padstack... Choose and existing padstack and modify it then save
under a new name. The slot appears in your drill legend, you then need to create the NC Route file.

Thanks for your reply joma,

actually i already created the oval slot and drill legend but when i create the nc-route file i cant open it in CAM350, it returns an error like "there is no header". i can export the data with ODB++ but i need to convert it into .art file or get rid of this error in nc-route. I think there is a problem with my nc-route file. I cant find out what it could be.

For comparison I have created an nc slot file which you can look at for differences in your setup. On the other hand you may need to change something in your CAM 350 but as I do not have that software I can not say.
As for working with gerber files you could simply draw and dimension the slot in your drill drawing and let the board manufacturer create it.The drawing could be saved as gerber or pdf. Its a possible workaround until you can get your nc setup working.

I couldnt view it also but i think you are right, it is caused by CAM350 viewer. i have send the .rou file to manufacturer and there appears the slot drills. Just creating the .rou file with the right parameters is enough for slot drills. Some viewers cant load the file but it is not problem.

Thanks a lot. 

Before 16.6 you needed to create a ncroutebits.txt that listed the nc route details. Since 16.6 this is created automatically. Take a look at:-