Cutting corrugated steel?

[OcalaWill]

Hi Guys,

I saw a video on Youtube of someone cutting corrugated steel on a plasma CNC table. Will the TM AVHC handle this? Has anyone here tried this on their TM? I am wondering what kind of setup parameters are required.

I hope I am not violating any forum rules posting this, but here is the video:

Thanks!

 

[Dnmeistr-LECS]

Yes you can cut it with the correct parameters, I will tell you you had better be real comfortable on how the AVHC works, what voltage does how the corner lockout behaves, pierce height, cut height, where you are going to start the cut from, your travel speed and amperage you are going to cut at, all play a role. In other words this is not for beginners.

 

[Conrad_Turbo]

Shouldn't this come down to how well the AVHC works? Lockout shouldn't be active, pierce height shouldn't be a concern as it's ohmic in sensing, cut height should be maintained by the AVHC and the cut speed and amperage is what drives the feedback to the AVHC. I'd be curious if the new all in one solution is capable, it all depends on how responsive it is without being overly sensitive. All comes down to PID control of the AVHC and how versatile it is, as parameters for cutting steel sheet wouldn't necessarily be the same for corrugate.

I can do a lot with my table and have it really dialed in, but I wouldn't try it as I'd probably crash my $700 Hypertherm machine torch. My budget is smaller than Lincoln's, I'd like to see a Torchmate demo video. Heck even cutting 29ga sheet at max table speed with some artsy fartsy pattern with AVHC active would be interesting too.

 

[OcalaWill]

Yes you can cut it with the correct parameters, I will tell you you had better be real comfortable on how the AVHC works, what voltage does how the corner lockout behaves, pierce height, cut height, where you are going to start the cut from, your travel speed and amperage you are going to cut at, all play a role. In other words this is not for beginners.

Do you think the Accumove II can handle it? It has "dynamic cornering" that eliminates the lockout ? Thanks.

 

[Larry Cameron]

Interesting. I cut 0.5mm copper sheet making 100's of butterflies. It warps/bends/moves all over the show. But I have a Hypertherm 45 using the 30amp consumables and cut about 20amps at 140ipm. Works great and using the Blue Screen AVHC

Larry Cameron
RusticMetalArt

 

[inkognito]

Conrad_Turbo is correct, corner lockout and ohmic sensing have no bearing upon the response as the vectorally corrected tip speed is constant as the XY axes contour the 'flat' surface. The operator doesn't need to know anything about height control. The objective of Accumove and it's HMI is to keep the complex functions 'under the hood' making the system easy to use.

Cutting corrugated isn't a problem for Accumove. Here's a link http://torchmate.com/tmu-3-avhc to a nice video presented by Mr Humphreys explaining how height control works with some footage of the torch rising up and over a piece of steel that could represent corrugated.

The limiting factor that determines the maximum gradient is acceleration rate of the Z axis. Assuming the slope falls within predefined limits which are a function of the mechanical load and torque profile of the motor then it will follow a corrugated contour. I'll personally donate $25 to a charity of choice that accepts online donations to the 1st poster that can tell me what the maximum gradient a Growth Series or new 4400/4800 table can cut. Show your method and use inch or mm units.

A major benefit with Accumove height control compared to competitive standalone products is the height is corrected in synchronism with a change in position to the contouring axes. A simplistic way to think about it is if the contouring axes haven't moved then the height will not have changed unless the material is so thin it's flapping in the wind then we have other problems to deal with.

Systems that run independent of the contouring axes are running asynchronous which means they are oblivious to what's really happening as they have such a narrow view. This leads to instability or hunting which results in filters such as a low pass being added that dampens the response and thus increasing the percentage of time the arc voltage is not what the user requested. The net effect is more dross, greater bevel angle and poor surface edge finish.

Just as a side note Conrad_Turbo, you make an interesting comment about PID. PID plant controllers are more appropriate to controlling heating systems which don't require fast response and having a long settling time doesn't negatively impact performance. A control loop modelled and designed for the application will give desired response across it's normalised minima\maxima operating range without the need to change parameters due to excitation of the input. The reason for changing parameters or adding adaptive control is to work around the inherent instability of PID loops which have a narrow bandwidth before instability and compromises need to be made to response through the addition of filtering. Interesting topic and thank you for raising it.

 

[Conrad_Turbo]

Conrad_Turbo is correct, corner lockout and ohmic sensing have no bearing upon the response as the vectorally corrected tip speed is constant as the XY axes contour the 'flat' surface. The operator doesn't need to know anything about height control. The objective of Accumove and it's HMI is to keep the complex functions 'under the hood' making the system easy to use.

Cutting corrugated isn't a problem for Accumove. Here's a link http://torchmate.com/tmu-3-avhc to a nice video presented by Mr Humphreys explaining how height control works with some footage of the torch rising up and over a piece of steel that could represent corrugated.

I've never seen that video and it was great to see! However the cutting demo looked like 14-16ga at 50ipm? That'd be a ton of low speed dross and is quite slow compared to other corrugate cutting videos that are on systems much older. Also I could imagine cleaning excessive dross off corrugate would be a PITA. I wouldn't be surprised if the previous gen AVHC (blue screen) could handle something that slow.

The limiting factor that determines the maximum gradient is acceleration rate of the Z axis. Assuming the slope falls within predefined limits which are a function of the mechanical load and torque profile of the motor then it will follow a corrugated contour. I'll personally donate $25 to a charity of choice that accepts online donations to the 1st poster that can tell me what the maximum gradient a Growth Series or new 4400/4800 table can cut. Show your method and use inch or mm units.

I'd come down to how fast the z-axis can accelerate, how accurate the ohmic value is and how quickly the controller logic can adjust without overshooting or reacting too slowly.

To be honest TM should be posting this with the specs of the machine. What is the max cutting speed with AVHC active? On the thinnest material? Etc... It's great that it's your own money, but TM/Lincoln needs to be more up front about the performance specs and videos to back them up. So far it seems like the AVHC combined with the controller just eliminated purchasing rebranded hardware; which allows TM/Lincoln to have more control over their supply chain, improve margins and have more control over the final design. Don't get me wrong I love my table now that I have a slick workflow and had enough seat time running table, but the new Growth Series doesn't have enough specs posted to interest me in upgrading.

A major benefit with Accumove height control compared to competitive standalone products is the height is corrected in synchronism with a change in position to the contouring axes. A simplistic way to think about it is if the contouring axes haven't moved then the height will not have changed unless the material is so thin it's flapping in the wind then we have other problems to deal with.

Systems that run independent of the contouring axes are running asynchronous which means they are oblivious to what's really happening as they have such a narrow view. This leads to instability or hunting which results in filters such as a low pass being added that dampens the response and thus increasing the percentage of time the arc voltage is not what the user requested. The net effect is more dross, greater bevel angle and poor surface edge finish.

Just as a side note Conrad_Turbo, you make an interesting comment about PID. PID plant controllers are more appropriate to controlling heating systems which don't require fast response and having a long settling time doesn't negatively impact performance. A control loop modelled and designed for the application will give desired response across it's normalised minima\maxima operating range without the need to change parameters due to excitation of the input. The reason for changing parameters or adding adaptive control is to work around the inherent instability of PID loops which have a narrow bandwidth before instability and compromises need to be made to response through the addition of filtering. Interesting topic and thank you for raising it.

I agree. I do like these technical discussions. We may not agree with everything, but my TM table has allowed me to meet a lot of new customers. At the same time I always can find flaws in nearly everything I do and buy. Everything can be improved and made better.

TM needs to include a "default" tool cutting library for TM CAD future releases. I spent two weeks building my library and can easily switch cutting any material with the proper kerf widths and cut speeds either with male (100% cut speed) or female tool paths (60% cut speed) for any holes. Also locking out the AVHC with the female tool paths so it doesn't crash due to the arc voltage changing due to the slower cutting speed. TM should do this for their line of plasma cutters...and offer the library with the TM CAD.

 

[inkognito]

I've never seen that video and it was great to see! However the cutting demo looked like 14-16ga at 50ipm? That'd be a ton of low speed dross and is quite slow compared to other corrugate cutting videos that are on systems much older. Also I could imagine cleaning excessive dross off corrugate would be a PITA. I wouldn't be surprised if the previous gen AVHC (blue screen) could handle something that slow.



I'd come down to how fast the z-axis can accelerate, how accurate the ohmic value is and how quickly the controller logic can adjust without overshooting or reacting too slowly.

To be honest TM should be posting this with the specs of the machine. What is the max cutting speed with AVHC active? On the thinnest material? Etc... It's great that it's your own money, but TM/Lincoln needs to be more up front about the performance specs and videos to back them up. So far it seems like the AVHC combined with the controller just eliminated purchasing rebranded hardware; which allows TM/Lincoln to have more control over their supply chain, improve margins and have more control over the final design. Don't get me wrong I love my table now that I have a slick workflow and had enough seat time running table, but the new Growth Series doesn't have enough specs posted to interest me in upgrading.



I agree. I do like these technical discussions. We may not agree with everything, but my TM table has allowed me to meet a lot of new customers. At the same time I always can find flaws in nearly everything I do and buy. Everything can be improved and made better.

TM needs to include a "default" tool cutting library for TM CAD future releases. I spent two weeks building my library and can easily switch cutting any material with the proper kerf widths and cut speeds either with male (100% cut speed) or female tool paths (60% cut speed) for any holes. Also locking out the AVHC with the female tool paths so it doesn't crash due to the arc voltage changing due to the slower cutting speed. TM should do this for their line of plasma cutters...and offer the library with the TM CAD.

It looks like Mr H is cutting quite heavy guage probably so it's visible for the video.

We've talked about the benefit of running the height control axis synchronised to the main contouring axis. Therefore the limit on a 4x4 is I think around 200ipm. It's limited by mechanical and stepper motor attributes.

It's straightforward to define the specification for avhc as we've discussed. However most manufacturers specify voltage resolution which means nothing and some will specify voltage accuracy. Empirical testing I've witnessed has shown height control with accuomve is accurate around +/-50mV across its cut speed range on a GS4x4.