Let me begin by explaining that this post is not a knock on the Siemens 840D controller. We have limited experience with the controller in regards to reliability as a CNC controller.
This post will, however, deal with two point of interest that we think are important for CNC personnel to know and consider when applying this CNC control to their shop.
- Control output ( G code ) compatibility with other CNC controls on the market.
- Ease and power in regards to conversational CNC programming
In the US market … Fanuc has been the dominant CNC control for many years. Reliable and abundant … Fanuc has been the go to CNC control for many machine tool builders. In the last 5 years or so … Siemens, Mitsubishi and to a lesser extent Fagor … have begun making their way into the US market … both in retrofit packages and factory installed on newer machine tools. Mitsubishi has mainly made their way through lower cost and good reliability … but one of Siemens’s selling features is their “conversational” approach to CNC programming.
While Mitsubishi has maintained their G code format … in fact Mitsubishi … smartly … maintains their 100% “fanuc compatible” G code format … they have given themselves the ability to attract those millions of Fanuc programmers out there by offering great reliability and the same programming format they already use.
Siemens on the other hand … only maintains their “fanuc compatibility” in their DIALECT or ISO mode. ISO mode is basically a secondary mode to the 840 control … and when in ISO mode many of the features of the control are unavailable. It is evident that the 840 pushed the user to the standard programming mode … which in Fanuc language is really a macro programming output. Difficult if not impossible to decipher and edit manually … and incompatible with any other G code format on the market.
If you have ever worked on a real wold shop floor … you know the problems and issues that “control incompatibility”. The inability for one G code format for one machine and one CNC control to function on another machine with another CNC control. This results in multiple “posts” if using a CAD/CAM system … and much re-programming or re-posting required to move programs from one machine to another. Not to mention the experience required and cost incurred for programmers who have the ability to program all formats for all machine on the floor … or the issues raised when they can’t.
When it comes to the Siemens 840 controller … compatibility with other CNC G code formats is a big consideration … it is NOT compatible. The 840 uses a macro format output … and as mentioned … difficult if not impossible to decipher and edit manually … and incompatible with any other G code format on the market.
TURNING : Here is an example an example of a turning canned cycle output per the following illustration example :
CYCLE95 (NPP, MID, FALZ, FALX, FAL, FF1, FF2, FF3,
VARI, DT, DAM)
Cycle parameter definitions :
- NPP : Name of the contour program
- MID : Maximum insertion depth (enter without sign)
- FALZ : Finishing allowance in the longitudinal axis (without sign)
- FALX : Finishing allowance in the facing axis (without sign)
- FAL : Correct finishing allowance for contour (without sign)
Versus a G71 / G72 Fanuc cycle … or a LAP cycle for an Okuma machine ( the two can be auto-converted between formats with our CNC XChange ) … the Siemens CYCLE95 is completely foreign … and is not compatible with any other G code format.
MILLING : Below is an example of a simple drilling cycle … so common on a Fanuc or Okuma control with a G73 cycle.
CYCLE83 (RTP, RFP, SDIS, DP, DPR, FDEP, FDPR, DAM,
DTB, DTS, FRF, VARI)
Canned cycle parameter definitions :
- RTP Return plane (absolute)
- RFP Reference plane (absolute)
- SDIS Safety distance (enter without sign)
- DP Final drilling depth/elongated hole depth/slot depth/pocket
- DPR Final drilling depth/elongated hole depth/slot depth/pocket
depth relative to reference plane (enter without sign)
- DTB CYCLE82: Dwell time at final drilling depth (chip breaking)
- FDEP First depth (absolute)
Again the complexity of the macro statement makes it overly complex and completely foreign to most G code programmers.
Being the pioneers and innovators in the field of G code conversion software since 1986 ( more info here ) … we know the issues that control incompatibility can cause on the shop floor … and the money and time lost through those issues. If you are contemplating bringing a Siemens 840 control onto your shop floor … we would encourage you to weigh the G code format and incompatibility issues that will result.
If this is your only and only CNC control … or control incompatibility is not a concerns … then let’s take a look at the “conversational” approach from the 840 vs. our PC based Kipware® conversational.
Conversational CNC Programming
Siemens calls their conversational programming ShopTurn … and we’ll let the Siemens YouTube video speak for itself …
In comparison … our Kipware® conversational :
We touch on many of the issues raised here between CNC control based conversational ( Siemens ) versus PC based conversational ( Kipware® conversational ). You can get complete details in this post : http://kentechinc.com/kipware_blog/pc-based-conversational-vs-conversational-cnc-controls/ To illustrate just a few key points :
- Ease-of-use and Power … Using the CNC control ( which is not a PC ) for input is cryptic and involves multiple changing menu bars. The PC is much more familiar, powerful and easy to use.
- Portability … programming MUST be done at the machine and in the confusion of the shop floor. PC based conversational installed on a laptop is portable so programming can take place anywhere and and can be used to program multiple machines … giving every CNC machine a conversational control.
Conversational programming in any format is designed for the simpler, everyday type CNC programing. The main feature is to allow for “shop floor programming” of these type of workpieces … leaving the complex 3D and mold type programming for the complex CAD/CAM systems. We also deal with this issue in depth in our post Shop Floor Programming vs. CAD/CAM Programming … see it in full HERE.
But what happens when “somewhat complex” and non-standard shapes require programming … through perhaps a simple drawing or DXF import. On a conversational CNC control … if it is even available … it is even more cryptic and difficult to program. But with the included Kipware® SketchPad … simple drawing and DXF import is simple and easy to program easy in Kipware® conversational.
The mere fact that any CNC control is no match for the personal computer for power and ease of use is in itself a big factor and speaks volumes when considering control based conversational vs. PC based conversational. And we didn’t even mention the cost !!
As I mentioned at the start of this post … we do not intend to knock the Siemens Sinumerik control in regards to it’s CNC control capabilities or it’s reliability. We are merely outlining what we consider to be “real world” points to consider in regards to conversational programming and control compatibility. If you are considering a conversational CNC control of any type … we encourage you to learn and explore additional points through the links below :
Kenney Skonieczny – President