March 17, 2013 No Responses

AVHC hole lockout

Here at Mint Design we’ve been doing some tweaks with our Torchmate CNC table.  One great feature of the table is the “auto” torch height controller, which adjusts the height of the torch in reference to the material.  So if the material bows or sits on the slats at an angle the torch will compensate for this and allow for a consistent torch to workpiece distance.  This ensures less chance of crashing the torch due to tip ups, minimal heat input, consistent kerf width and most importantly improves edge perpendicularity.  There is some drawbacks with the existing Torchmate system, which is why the AVHC hole lockout is created.

When cutting a hole the perpendicularity of the hole is important, having a hole with less taper ensures that that the hardware will fit and also improves the joint strength due to reducing stress concentration on the bolt vs. a tapered hole.  To achieve a hole with less taper you must slow the cut speed down, a typical rule of thumb is 60% the straight line speed.  This is a rule of thumb, because when a hole is larger in diameter the closer to 100% straight line speed is achievable  but if it’s a small diameter hole it requires a slower cutting speed.  The only major drawback to slowing down is more low speed dross, but this is a small price to pay for a hole with minimal to no taper.

Now how is this achieved with Torchmate CAD and the Torchmate 4 CNC program?  Assigning different tools for different tasks.  For example for one material type and thickness you will have one male toolpath and one female tool path assigned, the male toolpath will be 100% straight line speed and the female tool path will be 60% of the male cut speed.  The male toolpath will be assigned a turret #1, while the female will be assigned turret #3 (our plate marker has already been assigned to turret #2).  When a .dxf has been brought into TM CAD a female tool path is applied to all the inside features, and a male is applied to the exterior of the part.  The sequence is checked to ensure that all the inside features are cut first.  Then the tool paths can be exported via the “Machine”, “Output” function.

The Torchmate 4 CNC needs to be set up accordingly to read the G-code coming from the Torchmate CAD.  This is all done in the “Configuration”, “Programming”, “M-Code Definitions” and the “Configuration”, “I/O”, “Output Lines” section.  This will be explained in greater depth shortly.

Here are two screen shots showing the TM4 running offline to simulate what would happen.  Notice the hole being cut at 90ipm and the AVHC Lock being on, and once cutting the exterior of the part it is cutting at 150ipm with the AVHC Lock off.  This allows for the best of both worlds, less tapered holes and AVHC when it’s needed.

AVHC hole lockout AVHC hole lockout

One simply has to connect a 5v relay to the output of the controller and wire the relay to the corner lock inputs on the AVHC to enable this feature.  This will be described further once this is actually done.

Filed in CNC cutting

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