RDPJ Series Explained: Reading Model Codes and Suffixes
RDPJ is Karl Mayer’s model prefix for double needle bar jacquard raschel machines, and the figures that follow it (7/2, 7/3, 6/2) identify a specific build inside that family rather than a size or a year. The letters bolted on the end — EL, FB — change what the machine can do far more than the figures do, which is why two quotes with the same numbers can describe machines that will not make the same fabric.
This page is a map of the series. If you already know which build you want, the single-machine pages linked below carry the detail; what follows is how the line-up is divided and what to put in writing before you compare offers.
What the RDPJ family is built to make
Karl Mayer’s own series page groups the RDPJ output into four fabric families: knitwear produced in one piece without side seams, jacquard spacer fabric, multi-colour spacer fabric, and 4D-KNIT structures. That grouping is useful because it maps onto four different buyers, not four styling options.
The trade press fills in what those fabrics turn into downstream. Reported end uses include patterned spacer fabrics, garments knitted as a single piece, tapes and webbing, functional sportswear with openings placed at exposed areas for ventilation together with freedom of movement and quick drying, and pantyhose patterning.
One capability is worth pulling out because buyers routinely miss it. With an EL pattern drive working alongside the jacquard, a double needle bar raschel can knit a whole garment in one piece with body-mapped zones — different structures in different areas of the same blank. That is a garment-making decision disguised as a machine specification.
Reading the model code
No builder publishes a decoder ring for these codes, and you should be wary of any page that claims to give you one. What you can do is read the line-up itself.
Across the models on our own site, the figure after the slash moves with the jacquard content of the build: the RDPJ 7/3 page is headed Triple Jacquard Double Raschel, while the RDPJ 7/2 is described as a double needle bar jacquard placing freely positioned 3D patterns on spacer fabric. Treat that as a pattern visible in the range, not as a published rule — ask the builder to state the bar count in writing on the quotation.
The suffixes are where the real differences sit:
| Code element | What published sources attribute to it | What to confirm with the builder |
|---|---|---|
| RDPJ prefix | Double needle bar raschel with jacquard | Needle bar spacing range on offer |
| Figure before the slash | Identifies the build within the series | Exactly which build the quoted figure refers to |
| Figure after the slash | Moves with jacquard content across the range | Number of jacquard bars, in writing |
| EL | Electronic pattern drive; with jacquard, enables one-piece garments with body mapping | Pattern repeat limits and changeover time |
| FB | On the 6/2 EL FB, patterning on both faces of the fabric; 3D pattern shape, position and height fully variable | Whether FB is available on the build you are quoting |
Where the builds separate in practice
The RDPJ 6/2 EL is credited in the trade press with high output and a distinctive fabric appearance, attributed to its configuration rather than to any single component. Add the FB designation and the machine patterns on both faces, with the shape, position and height of the 3D pattern fully variable — anything from a shallow flat relief to a deep, cushioning form.
The jacquard system itself is the other separator. Piezo jacquard is reported to join thick sectioned fabric structures smoothly, which matters when your fabric changes thickness across the width or along the piece. If your pattern crosses a step change in structure, that is the question to ask, not the machine speed. Our jacquard system page covers how the selection mechanism works.
For fabrics that need many patterns rather than deep relief — curtains, home textiles, garment panels — the general jacquard double needle bar raschel build is the reference point, and the double needle bar raschel overview places it against the rest of the double bar range.
Which build fits which job
If your product is a garment blank knitted in one piece with different structures in different zones, then you need the EL pattern drive alongside the jacquard, and the figure after the slash is secondary. If your product is a patterned spacer fabric where the relief has to change height across the piece, then FB is the element to confirm first. If you are making tape, webbing or pantyhose patterning, then the pattern repeat and changeover time will decide your cost per metre long before the top speed does.
This does not apply if you are buying used. On a used machine the code on the frame tells you what left the factory, not what is on it now — pattern drives get swapped, jacquard bars get removed, and the plate stays the same. Inspect the machine against the code rather than trusting the code.
What to put on the enquiry
Four lines will save you a round of back-and-forth. Ask for the number of jacquard bars as a figure, not as a series name. Ask whether the pattern drive is electronic and what the maximum repeat is. Ask whether both faces can be patterned on the build being quoted. And ask for the needle bar spacing range, because that is what limits how thick a spacer fabric you can make.
Gauge, working width, speed and needle bar spacing vary by build and we do not publish figures we cannot verify against a specification sheet — get them from the builder on headed paper and compare like for like. For finished machines and the commercial side of the range, our sister site grandstarcn.com carries the product listings.
If you know the fabric you want to make but not the build that makes it, send us the fabric specification and the target output rather than a model number, and we will tell you which part of the range to look at. Start from our warp knitting machine types overview if you are still narrowing down the family, or write to us through the contact page.
Frequently Asked Questions
What does RDPJ stand for on a warp knitting machine?
RDPJ is Karl Mayer’s model prefix for double needle bar jacquard raschel machines. The figures after it, such as 7/2, 7/3 or 6/2, identify a particular build inside that family, and letters such as EL or FB describe the pattern drive and the patterning capability rather than the machine size.
What is the difference between RDPJ 7/2 and RDPJ 7/3?
Both are double needle bar jacquard raschel builds, and across the range the figure after the slash moves with the jacquard content: the 7/3 is presented as a triple jacquard double raschel, while the 7/2 is described as placing freely positioned 3D patterns on spacer fabric. Builders do not publish a decoder for the codes, so ask for the number of jacquard bars as a figure on the quotation.
What does EL mean on an RDPJ machine?
EL indicates an electronic pattern drive. Working together with the jacquard, it is what allows a double needle bar raschel to knit a whole garment in one piece with body-mapped zones, so different areas of the same blank carry different structures.
Can an RDPJ machine pattern both sides of the fabric?
On the RDPJ 6/2 EL FB the trade press reports patterning on both faces of the fabric, with the shape, position and height of the 3D pattern fully variable, from a shallow flat relief to a deep cushioning form. Confirm with the builder whether the FB designation is available on the specific build you are being quoted.
What can you actually make on an RDPJ machine?
Karl Mayer’s series page groups the output into knitwear produced in one piece without side seams, jacquard spacer fabric, multi-colour spacer fabric and 4D-KNIT structures. Reported end uses include patterned spacer fabrics, one-piece garments, tapes and webbing, functional sportswear with ventilation openings, and pantyhose patterning.
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