Which dosing needle for adhesive do I need for my application?
With the help of a dosing needle for adhesive, it can be applied precisely for a wide variety of applications. In some cases, a so-called mixing nozzle is also used to apply adhesives.
The following article explains the difference between dosing needles and mixing nozzles, which dosing needles and mixing nozzles are used and how.
Overview
- What is the difference between a dosing needle for adhesive and a mixing nozzle for adhesive?
- Which dosing needle should I choose and what should I look out for?
- How do I use dosing needles?
- Which mixing nozzle should I choose and what should I look out for?
- Advice on the subject of “Dosing needles and mixing nozzles”
- Frequently asked questions (FAQs) on the subject of “Dosing needles and mixing nozzles”
What is the difference between a dosing needle for adhesive and a mixing nozzle for adhesive?
The first question that arises is what the difference is between a dispensing needle for adhesive and a mixing nozzle for adhesive. Although both the dispensing needle and the mixing nozzle are used to apply adhesives, the dispensing needle and mixing nozzle differ in their main function.
A dispensing needle for adhesive is an attachment located at the end of an adhesive bottle, an adhesive cartridge or an adhesive dispensing system. The dispensing needle is used to apply the adhesive exactly where and in the quantity required. The dispensing needle is usually hollow on the inside.
The main function of a dispensing needle is therefore the precise dispensing of adhesives.
Applications for dispensing needles: Application of 1-component adhesives or already mixed 2-component adhesives in the form of dots, lines or fine beads; the application of very small quantities is also possible.
A mixing nozzle for adhesives is an attachment that is usually mounted on a double cartridge of 2-component adhesives (2K adhesives). The mixing nozzle is used to mix the two components of a two-component adhesive (usually resin and hardener) in the correct ratio so that the adhesive can be applied ready for use in the desired application. Inside the mixing nozzle there is usually a mixing element, for example a spiral.
The main function of a mixing nozzle is therefore to mix 2 components (usually resin and hardener) so that they react with each other in the desired form, in particular to start a curing reaction.
Purpose of mixing nozzles: Automatic mixing of 2-component adhesives with consistent quality and direct application of the mixed components.
Which dosing needle should I choose and what should I look out for?
When selecting the right dispensing needle for adhesive, you need to consider various factors, including
- Inner diameter specified by the manufacturer: The inner diameter of the dispensing needle influences the flow rate of the adhesive and the amount of adhesive applied, i.e. the size of the drops.
Adhesive dispensing needle manufacturers such as Techcon specify so-called gauge values for their dispensing needles, to which the manufacturer assigns certain inner diameters and colors. However, Techcon ‘s colors do not match the colors that are assigned to the corresponding gauge values for medical needles according to the ISO 6009 standard.
- Needle length: The longer the dosing needle, the easier it is to reach hard-to-access areas. However, longer needles can make the flow more difficult.
- Dispensing needle material: Dispensing needles are available in various materials, such as metal or plastic, including Teflon. Teflon dispensing needles resist cyanoacrylate clumping, for example.
- Shape of the dosing needle: There are straight dosing needles, curved dosing needles, conical dosing needles and flexible dosing needles. Curved dispensing needles and flexible dispensing needles are suitable for hard-to-reach areas. Conical dispensing needles prevent blockages.
- Design and treatment of the dispensing needle: There are also special designs of dispensing needles, such as dispensing needles with crimped cannulas, in which the stainless steel cannulas are cut to the exact length and deburred. The needles are then crimped into a secured aluminum insert. They are then molded in polyethylene.
Electrolytically polished needles are a special treatment for dispensing needles, which ensure a constant flow of material.
- Working pressure: Depending on the dosing needle, the maximum permitted working pressure can also vary.
- Connection types: A distinction is made between the general worm thread, the Luer lock connection (standardized worm thread) and the bayonet connection.
- Adhesive: The adhesive used is also decisive for the selection of the right dispensing needle, including the viscosity of the adhesive and the type of adhesive, i.e. whether it is a light-curing adhesive, for example.
There are manufacturers who offer so-called dosing needle sets containing the most common dosing needles in order to test which dosing needle is best suited to the respective application.
Which dispensing tip is suitable for which adhesive?
The different dosing needle types are also suitable for different adhesives.
Conical dosing needles
Techcon’s TT Series conical dispensing needles are suitable for medium and high viscosity adhesives as the conical shape improves material flow. As the standard TT series is made of polyethylene with a UV light-blocking additive, they are suitable for light-curing adhesives.
Flexible dosing needles
The flexible dispensing needle for adhesive from Techcon’s TS-P series is suitable for cyanoacrylate adhesives. If necessary, this dispensing needle can also be shortened.
Dosing needles with Teflon
Dispensing needles with Teflon are particularly suitable for low-viscosity adhesives and cyanoacrylates, i.e. instant adhesives. This is because these Teflon dispensing needles resist cyanoacrylate clumping.
Dosing needle with stainless steel cannula
Techcon’s TE series dispensing needles with straight or curved stainless steel cannula do not specify a particular adhesive for which these dispensing needles are suitable. They are therefore dispensing needles that can be used for a wide range of adhesives.
Here you can buy TE series dosing needles from Techcon in the abovo online store.
How do I use dosing needles?
Depending on the area of application, the dispensing needles are attached to different end points. In a dispensing device, for example, the dispensing needle can be attached to a dispensing tube or a dispensing valve. An adapter may be required if the appropriate thread for the desired dispensing needle is not available, such as a Luer lock adapter.
With Loctite bottles or cartridges , the dosing needle can either be attached directly, provided there is a thread suitable for the respective dosing needle. Otherwise, an adapter would have to be fitted in between, for example for a Luer-Lock connection.
Which mixing nozzle should I choose and what should I look out for?
When selecting the mixing nozzle, it is particularly important to ensure that the mixing nozzle is designed for the correct mixing ratio, for example a mixing ratio of 1:1. However, there may also be 2-component adhesives that require a different mixing ratio, such as 2:1, 4:1 or 10:1. In some cases, mixing nozzles are included with the respective adhesive product.
The length of the mixing nozzle determines the degree of mixing, whereby the required length depends on the design of the mixing nozzle. The conventional design is spiral and round. A newer type of mixing nozzle is square and mixes the two components more efficiently. Square mixing nozzles can therefore be shorter and thus reduce waste.
Before attaching the mixing nozzle to a cartridge, for example, you should first squeeze out enough of the two components until the planned quantity comes out of both openings at the same time.
After you have attached and fixed the mixing nozzle, you should discard the first 10 centimeters that you apply from the mixing nozzle on a base, i.e. do not use it.
You can buy the following mixing nozzles from the specialist adhesive wholesaler abovo:
Please also read our article “ HireaLoctite dispenser and Loctite light curing system“.
Advice on the subject of “Dosing needles and mixing nozzles”
As every application has specific requirements, it is best to consult our experts at abovo, the specialist adhesive wholesaler, so that together we can find out which dispensing needle for adhesive and/or mixing nozzle is right for your application.
For advice, you can simply call or e-mail our adhesive experts at abovo:
- Telephone number: +41 32 552 44 44
- E-mail: info@abovo.ch
If you contact us by e-mail, we will reply as quickly as possible.
