Digitising and Multi-Head Machines

While similar, digitising for multi-head embroidery machines can present its own unique set of challenges. However, one thing that is nice about evaluating a digitising project on multi-head embroidery machines is this; regardless if the machine has 2 heads or 30 heads, if a problem is apparent on all sewing heads then the issue can almost certainly be attributed to the digitising. If the problem only shows up on one head, but embroiders nicely on all of the other heads, there is almost certainly a mechanical issue on the head showing the failure.
This might seem obvious but one of the first questions I will ask when presented with “why isn’t this design sewing nicely on my machine?” is: “are you embroidering on a single-head or multi-head machine?” This is never meant as a method to shift responsibility from the programmer to a piece of equipment but it is really helpful to know the facts in order to provide the best solution to the problem.

If all heads on an embroidery machine are in good repair and the machine itself is well maintained then in theory it should not matter if there is one head or many. But the reality of this universe is moving the mass of a multi-head machine’s pantograph will induce some considerations the programmer needs to be aware of. Furthermore, some machines are simply better (higher quality pieces of equipment) than others.

Embroidery quality is closely tied to the precision of the pantograph movement as well as the relationship between all of the other moving components on an embroidery machine. An experienced programmer knows this and will often adjust a design to match the characteristics of a specific machine. One of the most frequent adjustments a programmer will make is to add a little more Pull Compensation to designs targeted for multi-head equipment. Since a multi-head machine needs to swing more mass when moving the pantograph, it may be necessary to compensate for this with slightly wider columns in areas with tighter registration. The machine manufacturers might say I am nuts to make this claim but I can state categorically (from years of experience), for optimum performance it might be necessary for a programmer to adjust a design even if two of the exact same multi-head machine models are sitting right next to each other on the same production floor running the same design. This could also be true on a single head machine but it is easier to tune a design for a one head than a multi-head.

Poor programming will impact a single-head machine just as much as a multi-head machine but on multi-head machines those problems will be multiplied by the number of heads. Here are a few areas where poor programming can impact embroidery production. However, remember the test; if the problem is one head, it is probably the machine; if the problem is on all head, it is probably the digitising.

Thread breaks – Poor programming will cause thread breaks. However, the programming has to be really bad for this to be the case. What you would look for here is designs that are overly dense. If the stitches are packed in too tight, thread breaks can be the result.

Trims – What is most important to determine here if the problem is with the stitch tie off which will cause a “pull out” or if the thread is actually breaking at the point of the thread trim. Digitisers use many different methods to tie off thread before and after a trim sequence. The techniques for this are too elaborate for the scope of this conversation but if you think you are getting “pull outs” (the thread pulls out of the needle in the trim process) instead of thread breaks, you should discuss tie off methods with your programmer. This phenomenon can also happen when the design starts sewing again in a new location. In this case, you look to the “tie-in.”

Registration – Registration issues are when the border (be it walk, bean, satin etc. stitch) do not “register” with the area they are supposed to trap. This is an area that more times than not is related to the programming, but again see “the test.” If this is happening on one head than look for things like bent needles, spoiled thread and poor tension. If this is happening on all heads your programmer needs to edit the design no matter what he might say.

Tension – There are a few symptoms which will manifest on both multi-head and single head embroidery machines that are rarely the fault of poor digitising. These include: white thread showing on the top of the design and “bird nesting.” Both of these are related to tension and whilst a poor programmer can aggravate the condition programming alone will almost never cause the problem.
White thread on top of a logo (some people call this, salt and pepper effect) is caused by poor tension. What is happening (usually) is the top thread tension is too tight in relation to the bottom thread tension and the top thread will pull the bottom thread to the top of the embroidery. This is fixed by adjusting tension not editing your embroidery design.

Bird Nesting is the mother of all embroidery failures. It is characterised by an event where it looks like your embroidery head is trying to pull your entire garment through the needle hole in your throat plate and will destroy any garment that is unlucky enough to be on the machine when it happens. This problem is never caused by programming and is almost always caused by a failure of the bobbin case on your machine. Often times lint will build up between the tension spring and the bobbin case. When this happens, you cannot adjust the tension of the bobbin spring and the tension on the bobbin becomes so loose, the Bird nest is the result. When this happens, save yourself a lot of headaches and replace the bobbin case. Don’t try and clean it. When this happens, the spring is sprung and there is no going back.

Programming for single-head embroidery machines and multi-head embroidery machines is fairly similar but there are “tricks to the trade” that seasoned programmers employ in order to facilitate the highest quality, production friendly designs. This does not mean a design programmed for a single-head will not work on a multi-head or vice-versa. What it does mean though is if you really want to optimise your production environment you should have the conversation with your programmer about your exact equipment mix and ask him what he can do help you improve both the quality and efficiency of the designs that are produced by your equipment.