Zéro Axis:

•  Displacement speed:  
• Question: How is the displacement speed calculated in the Zero Axis window ?
• Answer: The speed is calculated from the highest value of X and Y step delays when the displacement requires both X and Y movement. For single axis moves (only one of (X,Y) coordinate change) the speed is calculated from the step delay value for the corresponding axis.
• Not enough torque from motors when commanded from Zero Axis  window 
• Question: When commanded from the Zero Axis window (the one with arrows), the motors exhibit strange behavior: they seem to loose steps as if they may be overspeed, and the torque appear to be very weak.
• Answer: The scheduling of commands (with Zero axis arrows controls) is done using Win95 and Windows timers. No surprise that something goes wrong from time to time....
• Problem in Zéro Axis 
• Question: In the current version, is the displacement speed of the Zero Axis menu calculated from the max of both X and Y step delays ? 
• Answer: Temporary workaround: When you are moving trolleys to adjust the maximal speed for both axis, you should give the same value on both axis.

• Alignement demi hauteur:  
• Question: 007: What is the use of half height alignement when cutting X leading edge ? 
• Answer: Gérard: I consider as usefull to be able to adjust the height of the X cut  in the extrados and intrados foam beds. Many reasons, 
• Thickness distribution (extrados/intrados), with respect to the section axis, or the section axis itself cannot always be centered in the foam block. Generally, the cut is placed in the lower half of the foam block.
• Sometimes we may want to align (in height) the extrados or (less often) the intrados of root and tip airfoil sections. Or quite simply to have some dihedral directly set within the block. In those cases, without adjustment, the X cut for intrados or extrados foam bed will not be finished and it will be necessary to terminate it manually with a knife....What a pity ! 
• Leading edge notche:: 
• Question: How to cut a notch during the cut for a balsa leading edge ?
• Answer: Enter a negative value for "l" allows to make room for a balsa stick at LE.
• Answer: You can use a negative leading edge margin value to leave room for the balsa LE.
• Dressing leading and trailing edges: 
• Question: I have cut yesterday a wing with the block trimming  options from the cut menu. In my configuration, leading and trailing edge clearing are activated. During the cut, only the trailing edge trimming has been done. Is it a normal behavior ? 
• Answer: This depends upon the selected leading edge cut option. The block trimming cut (during wing cut) is actually done if the continutation is horizontal or if the leading edge is negative.
• Leading edge cut with Spline:  
• Question:Olivier: Oups after the cut of a MH24 section with a X leading edge (version 1.04) without Spline the result is catastrphic....a new leading edge type has been invented...... To get a corect X cut it is necessary to use splines. Is there an explanation ? 
• Answer : Olivier: in fact, the big problem arise with coordinates files which does not include a 0,0 coordinate point !!!! 

• Installing the block for the cut
• Question: Doit-on mettre des poids sur le bloc durant la découpe ? 
• Question: Is it mandatory to put weights over the foam block during the cut
• Answer: Gérard: When I cut a wing I use to set a wood plank as a weight over the foam block. Especially with extruded foam blocks which are never perfectly straight and which are subject to warping during the cut. The plank weight helps to maintain the block on the table and to relax tensions in the foam and avoid warping.

• Quality of a cut:: 
• Question: Does the foam type have an influence over the result and the precision of te cut ? 
• Answer: There is little influence of the foam type. The result quality will depend upon the tip cut speed, the wing streamline (CNC use root speed as a basis), the thickness of the part to cut (the thinner, the more warping you get, caused by heating). Last thing, open cut starting with extrados give usually better results.
• Question: How to improve your cut ? 
• Answer : Once everything is OK for cutting foam (electronic, mechanic, softwrae), it is interesting to gather precise informations from each experience of cut. For instance, keep track of : 
• Type, diameter, length of cutting wire, together with voltage used during cut 
• The actual cutting speed (at root)
• The type, thickness, and manufacturer of foam (residual constraints within the block are changing with foam manufacturer and thickness).
• A measurement of the section thickness and the thickness of the actual trajectory of the wire (this delivers and indication on the wire kerf during the cut).
• A subjective evaluation (1 excellent down to 5 very bad) of the final result  (accuracy of the cut, finish, etc...) with perhaps an associated comment.
The accumulation of these data will allow a better adjustment of cutting parameters.
• Sweep:  
• Question: What is the influence of wing sweep on the cut ?
• Answer:  With extruded foam (more than with expanded), the clever option of shaping the LE during the cut does not give good results. The wire goes many times past the same location in front of the LE and this strengthen the dressed up part. Then when it is time to restart with cutting the airfoil section, the wire remains blocked for a while until the strengthened foam melt. Unfortunately, the trolleys are still moving so the leading edge is wrong. The more sweep, the worst the effect.

• Error Messages: 
• Question: With version 1.05, I notice while loading batman that you have added an error message about file points. Can you give some explanations ?
• Answer: It is a detection of multiples direction changes over the X axis. Normally, for an airfoil section, there is only a single direction change at leading edge. This is only a warning which may be safely ignored for cases like your bat or other complex shapes. On the other hand it may help to locate some default over an airfoil  section data file.
• Question : My problem: the SW does not seem to work with Windows98: No problem with Windows95 (but at the beginning, with a 486dx2/66 I have only installed a minimal configuration and a lot of dll were lacking). Under Windows98, (installed on a PentiumII), when starting the software I get the message telling  "impossible d'initialiser le driver pour l'interface GP99" [Impossible to load the GP99 interface driver]. Are the files originating from CNC.zip all stored within the same directory ? 
• Answer: 
• Olivier: Is your PC a laptop ? Do you know the physical adress of your parallel port ? Usually LPT1 = 378.
• Sebastien: The message disappear after bios modification and setting adress 278/IRQ5. I do not know if the interface works properly. 
• Laurent: Strange. I use the software on a laptop running Windows 98 and the GP99 interface board without problem. My PC is configured with LPT1 adress 378 IRQ7. The porblem may come from the bios configuration for the parallel port. Many bios are able to configure different modes for the parallel port and Gilles's driver read and write the parallel port which should be configured in EPP mode or bidirectional mode. By the way, which version of Windows98 are you using W98 SP1, W98 SP2 or W98 SE ? 
• Sébastien: I've got many information, but the problem remains. Port adress is 378/IRQ07. The port works well because I operates it with a Zip drive (which is removed before starting the SW). I have also a small digital scope which works perfectly when connected ??. My windows 98 version is the very first, shipped with the PC (4.10.1998). The PC is a desktop model (PII 266MHz). However, it is full and I have no more spare slot, so may I get some conflict ? 

I should be surprised....In the meanwhile I am goin to restart the 486, everything works wel with it and this allow to leave a PC permanently in the workshop... 
• Olivier: No, I think we should continue to search a solution, in order to prevent this type of problem to occur again. Are your ZIP or scope drivers automatically loaded so they may disturb normal operation ? When tuning your timer, does the software recognize the timer ? 
• Gilles: In principle, there are two possible error causes. Either the driver is not in the CNC directory, or the driver cannot vectorize the board IRQ on // port. The driver uses IRQ 7 (fixed value), so one should insure that this IRQ is available and configure the hardware to use this IRQ (system/driver configuration). On the other hand, the IO address is automatically determined. It is read by the driver from location 0x408 (initialized by the BIOS). We should check that the driver configuration is identical under Windows 95 and 98. Last thing, CNC works only with LPT1 port, and does not require the interface board to be connected in order to operate.
• Sébastien: Other people who are getting the same error message also have a Zip on their parallel port. After removal of all memory resident drivers, the problem still occurs???. I've also set the parallel port Bios configuration in EPP mode.. 
• Gille-Chevlerias: After trying many solutions, here are my results. On my PC everything works with win95 and win98(first version), even with installed zip. However, if I reload all my disk image the problem comes back. So I am going to reinstall all my drivers one at a time to identify the origin of error. It does not semm to come from Windows 98.
• Gille-Chevlerias: I finally identified the origin of the problem of the error message "impossible d'initialiser le driver pour l'interface GP99", it comes from the my sound card driver (Ensonic). You should go in System properties/Drivers/Properties of sound and video system and in the setting tab remove the setting "allow lpt interrupt sharing" .  The message occurs even without board connected. If you want more details my address is gilles.chevalerias@fnac.net . II hope this will help.
• Gerard: Can this problem occur under windows95 ? As we have done with interface boards problems (file PB_electronique.txt), could you Gilles create a similar file for this type of problems and add it to the CNC archive? 
• Gilles: So the problem is linked to both driver and OS version. However, i am not sure of my IRQ sharing between drivers. There may be some small differences here between win95 and win 98...It is very dependant on the PC and I cannot test this at home.
• Too high speed problem: 
• Question: During a demo saturday with the 0.57 versionand the attached file I have got the message "Vit. sup. sur axe X droit ... Deplacement jusqu'a l'entree du bloc".  With version v0.58 the result is the same. After investigations, it appear that if I increase the X offset from 20 to 40, I can get the cut done. During the displacement toward the block, the software manage the root cut speed in relationship with the material ?

Here are the parameters of my foam cutter:
• Over  X : 48 steps - screw lead 1mm - Minimal step delay  4.5 ms 
• Over Y : 48 steps - screw lead 1 mm - Minimal step delay 5 ms 
• XgXd : 1274 
• X zero Position : 50 mm
• Answer: To do such a cut, there are two trajectories with inverse sweep.We are having a problem at block entry because the block is too far from the right axis, which leads to a speed limit. If the block is moved toward the right axis, then we will be blocked afterward during the cut because of the inverted sweep (the same speed limit problem arise on left axis). 

Solutions: 
• diminish the cutting speed 
• bring both axis closer 
• I can modify the program so that the entry up to the edge of the block will proceed at the maximal speed allowed by the sweep on both axis rather than at the trajectory cutting speed. This is possible because we are not in the block yet. Well I see I have got work for my holidays..... 
• Question: The Heater : For two hours now I am trying to cut a wing and the best speed was 1.3 mm/s, then I uncheck the spline option and now I can go through at a 2.7 mm/s speed (almost doubled). My question is why the spline function slow down the cut ? (Isn't the spline function a smoothing of the curve ?). This should not slow down the cut !!! The distance to travel for my cutting wire is the same (with the same section, with very small differences due to smoothing).
• Answer: The Master: It is a problem of instantaneous speed between two points. the spline does not generate the same points than the basis algorithm which takes points on the straight line between to coordinate set. Together with the normalization, from time to time some strange effects may occur at leading edge (higher curvature). About the computation of maximal cutting speed, this is equivalent to calculate the limit between two points. So it is necessary to simulate a cut....Possible but no so easy. Furthermore, this could be slow and tedious for low-end PCs and big wings, so it can not be done evrytime. To be considered with a pushbutton in the cut menu......in the future. 

• Type of stepper motor: 
• Question: For wich type of stepper motors is the CNC table optimized ?
• Answer: The machine is optimized with 48 steps/rotation motors, together with 1mm screws lead. If you are using motors with more steps, you may consider using a higher screw lead value.
• Number of motor steps: 
• Question: How to increase the number of steps of your motors ?
• Answer:  If you want to test the cut with a greater number of steps, modify your electronic (5804 wiring) so they are working with half steps (96 half steps/turn).Then fill in the number of steps/turn variable in the CNC configuration menu with 96 rather than 48. 

• Number of  points:  
• Question: What is the maximal number of points that the CNC software can handle in an airfoil section file ?e
• Answer: Gilles: 512 for the loaded file. The limit comes from the original software. But I can do a dynamic memory allocation.

 
• File Format :  
• Question: Is the *.cnc file format identical between each versions ? 
• Réponse:  No, depending on functionnality added during development, the file format may evolve between versions.

• Stopping Cut:  
• Question: How to halt the program during a cut or a move ? 
• Réponse:  PUp to now, the only solution is to break the program through  CTRL+ALT+DEL and then  kill the task. [improved in recent versions] 

• Documentation  
• Question: How to get rid of the documentation background when printing to avoid spoiling the printer ink cartridges ?
• Réponse:   Well, in your browser, you configure File->Page Setup and then uncheck the "Print Background" field.