The document discusses powder grinding and summarizes the history and modern processes. It describes how early grinding methods involved crushing or grinding grains between two stones. Modern powder grinding uses attrition between rotating discs. Screening controls powder quality by sorting particles by size through mesh screens. The document proposes a new global standard for dry flow funnels to improve consistency in measuring powder quality.

1. Shanghai December 2009
What is Powder Grinding?
什么是磨粉 By Ian Hansen
1

2. 脱氧核糖核酸
聚合物 添加剂 研磨 颜料 制模 加工后
Powder
quality
2

3. GRINDING OR PULVERISING BACKGROUND
研磨的背景知识
Size reduction techniques have been used for thousands of
years. Early forms of size reduction were crushing or grinding.
In our industry we use an attrition (or abrasion) method. The
rubbing of a particle against a rigid force.
The technological advances over the years have developed a
wide range of varying mechanical size reduction methods.
A boy grinding wheat
with a single grindstone
减小颗粒的技术已被运用百年。早期的方法是通过敲碎或研磨。
在滚塑行业我们使用磨损的方式。近年来，随着科技的发展，我
们研发出大量的通过机械手段减小颗粒尺寸的方式。
3

4. GRINDING OR PULVERISING BACKGROUND
聚乙烯由于其较低的软化和溶化温度，机器研
磨非常困难。
因此，圆盘磨粉机成为滚塑业最成功的研磨聚
乙烯粉末的机械装置。
The grinding of polyethylene is difficult on most size
reduction machines because of its low softening and
melting temperature.
As a result, the disc attrition mill has evolved as the Millstones mechanised by the
most successful mechanical device to grind circular movement of an animal
polyethylene into powder for the rotational moulding
industry.
4

5. THE PAST – BUHRSTONE MILL
过去
The grinding action used on today‟s plastic materials is described as a combination of
impact, shearing and attrition.
The disc or attrition mill used to grind polyethylene powder is a modern counterpart to the
early Buhrstone mill, which is considered the oldest form of grinding mill, and was the
“millstone” used for flour production.
如今，塑料研磨被称作撞、切、磨的综合
技术。
用于研磨PE粉的圆盘磨粉机代替了早前
的buhrstone磨，这是最早的研磨机形式，
也用于面粉制造。
5

6. THE PAST – BUHRSTONE MILL
两块水平的圆石放在一起，一块石头转动带动另一块，石头上刻有槽纹。
当谷物放入上层石头中心后，槽纹会使谷物逐渐移向石头边缘。
德国Pallman公司，成立于1903年，是一家面粉研磨机企业。1955年，Pallmann研发了一款
能在常温下研磨塑料的研磨机。
固定石
Two horizontal circular stones (plates) were arranged so that one rotates relative to the
other. Grooves were cut into the stones and were usually parallel to one radius of the
segment.
The effect of these grooves, after the grain was fed
into the centre of the upper stone, was to cause the
grain to gradually move out towards the circumference. 旋转石
The Pallmann company in Germany was founded in 1903, as a flour mill
company. In 1955 Pallmann developed a mill that was able to grind or
pulverise plastics at ambient temperatures.
6

7. THE PRESENT – POLY GRINDING MILL
Typical schematic arrangement
现在——聚乙烯研磨机
通
过
气 气旋
流
输 气塞
送 粉末加料斗
颗
粒
染色颗粒 振动筛
粉末包装
研磨室 鼓风机

8. THE PRESENT – POLY GRINDING MILL
Actual arrangement
Particles conveyed by air stream
Air
Cyclone
Air
Blower
Air Lock
Vibrating
Sieves
Grinding
Chamber
8

9. The present – Poly Grinding Mills or Pulverisers
The grinding plates are set with typical clearances of 0.3mm. The rotating plate can be
rotating at speeds of up to 5000rpm. The grinding tooth profile, clearance between the
plates, the speed of rotation and mesh size are selected depending on the material to be
ground and the required particle size.
研磨盘为0.3mm常规间隙。转速可达每分钟5000转，研磨齿形，研磨盘间距，转速
和筛网的尺寸取决于被研磨材料和所需颗粒尺寸。.
在
feed
Grinding mill
housing
出粉
discharge disc
9

10. Coloured pellets being feed into the grinding chamber
上色颗粒进入研磨室
Feed In
在
10

11. Grinding Plates or Discs 磨盘
The stones have been replaced by steel discs or plates arranged vertically or horizontally,
typically with one stationary plate and one rotating plate.
石盘已被水平或垂直放置的铁盘所取代，通常是一个固定磨盘加一个转磨盘。
垂直磨盘
Vertical grinding plates
横向磨盘
Horizontal grinding plates
11

12. Grinding
Rotating Disc or Plate
Discs 磨盘
Grinding teeth
segments
The Discs have a series of
serrated teeth cut into them.
磨盘上的锯齿
12
Fixed Disc or Plate

13. Grinding Plates Sharpening
The sharpness and angle of the cutting teeth needs to be managed to maintain
output rate, but also powder quality.
There is cost involved in shutting down machines to sharpen the discs, which
is typically balanced against the output rate. Kg/Hr
Discs have a finite life.
通过控制锯齿的锋利度和角度来保持产
出率和粉末质量.
关闭机器锐化磨盘时,会产生成本，通常
与产出率成反比。
磨盘使用寿命有限。
ICO Gainsborough, UK 13

14. Grinding Plates Sharpening 磨盘锐化
磨盘重新锐化是一项重要的维护工作。大多数锐化工作由第三方工程公司操作。
Re-sharpening of grinding discs is an important maintenance task. Most sharpening is
undertaken by 3rd party engineering companies
14

15. Screening process 筛选过程
The old Buhrstone mill controlled the fineness of the product by pressure between the two
stones and by the grinding speed.
In today‟s grinding machines, the grinding speed is fixed, and therefore the fineness of
powder is controlled by the selection of both the grinding teeth profiles and the size of the
screens used in the sifter.
粉 旧时Buhrstone磨粉机通过石头间的压力和研
feed in 磨速度来控制产品质量。
如今的研磨机，磨速是固定的，因此粉末质量
由锯齿形状和筛网尺寸来控制。
Screen
Multi deck screens. The 多层筛网。红色超尺寸的粉末，
oversize material (red) flows
over the entire screen (blue)
流过整个筛网层。
area. Wood frame – grey. 15
15

16. Screening process
从磨盘流出来的PE颗粒被送去过滤。
同一批粉末进入筛网，但分量批流出。
尺寸符合要求的颗粒能够通过筛网，偏大的颗粒最终回到研磨室，重新经过磨盘
研磨。
The polyethylene particles that exit from the grinding plates are conveyed to the sifter
unit.
One material enters the stack of screens, and two materials exit the screens.
The correct size particles pass through the wire mesh screens, while the OVERSIZE
particles eventually are returned back to the grinding chamber, to pass through the
grinding plates again
特大型粉
末粒子
Screen
16

17. 进粉 Sifter Units
Powder Feed
IN
进
粉
IN
Powder OUT
出粉
Oversize 出粉
Powder OUT
偏大粉末流出 OUT 17

18. Powder Screening 如今使用的筛网通常是回旋式的,筛网上有多层带网的木制
mesh
框架。粉末经过网衣后就可识别大小。 30目=95%粉末直
screens 径小于0.06毫米
Sifters (also called screeners) used today are typically the
gyratory type. These have multiple stacks of wooden frames
which have wire mesh screens stretched on them.
The powder is normally known after the wire cloth used in the
screens.
Wooden 30 mesh = 95% of powder
frames is less than 600 microns
木框
Stainless Steel
screening cloth (mesh)
筛网
18

19. Powder Quality 粉末质量
The grinding process has evolved over time, from the stones discs to metal discs. Despite
the advances in technology, variations still occur from batch to batch, and can result in
variable moulding outcomes.
Having the ability to identify significant variations in powder quality can minimise
unsatisfactory moulded products.
研磨工艺不断发展，从石盘发展到金属盘。
尽管技术发展，不同批次的产品仍然存在
偏差，幵会导致不同的成型结果。
若具备辨别粉末量明显偏差的技能，就能
最大程度减少未达标模具的数量。
粉漏斗
19
Pictures : www.rotationalmoulding.com

20. Powder Quality 粉末质量
.
干流是一种测试在滚塑过程中，磨粉在模具内如何流动的方式。干流会影响粉末池
内的热传递，以及粉末如何在模具表面分布。干流通常取决于颗粒形状，以及大小。
未经很好研磨的颗粒会有小尾巴和小绒毛，这两点使粉末流动性较差，导致壁厚不
均匀。
Dry flow is the measure of how a powder will tumble and flow in the mould during the
rotational moulding process. The dry flow affects the heat transfer in the powder pool and
how the powder distributes itself over the mould surface.
Dry flow depends mostly on the particle shape, and to a lesser
extent particle size.
Particles that have been ground poorly will have „tails‟ and tend to
be „fluffy‟. These two characteristics will give the powder poor flow
properties - possible leading to uneven wall thickness, bridging
across narrow recesses and a high void content within the
moulded product.
测试干流是唯一最常见的控制粉末量的方法。
Measuring Dry Flow is the single most
common method to determine powder „quality‟
20

21. The new Global Standard 新的全球标准
In June 2009 the representatives of the worldwide rotational moulding
organisations held their annual ARMO Board meeting.
2009年6月，全球的滚塑机构代表召开了滚塑机构联盟（ARMO）年会
ARMO (Alliance of Rotational Moulding Organisations) 滚塑机构联盟
Britain BPF, 英国 BPF
Ireland IRMA, 爱尔兰
Central Europe ARM-CE, 中欧
Central and Eastern Europe CEE-ARM, 东欧和中欧
Nordic ARM, 北欧
Italian AISR, 意大利
French AFR, 法国
South Africa ARMSA, 南美
North America ARM-I, 北美
India STAR Society of Asian Rotomoulders, 印度亚洲
and of course Australasia ARMA. 澳大利亚
It was agreed that we would adopt a new worldwide standard for Dry Flow funnels.
Each individual organisation is currently obtaining local member approval.
最终一致通过应当采取一种新的干流测试漏斗全球标准。各个机构目前正
在征求当地会员的同意。 21

22. The new Global Standard 新的全球标准
This funnel specification has a number of improvements, with the most significant being
smaller tolerances on the outlet hole, to minimise the significant testing differences between
the old funnel standard.
这一漏斗规格有所改进，明显减小了出口孔尺寸偏差，以减小使用原漏斗标准存在
的明显测试偏差。
Current standard allows exit hole cross sectional area variation of +/- 20%
New standard allows an exit hole of 9.99-10.01mm. An area variation of +/- 2%
现行标准，允许出口孔直径偏差为 + / - 20％
新标准仅允许偏差为+ / - 2％
ARMA are now able to offer the new dry flow funnel around the world for an
investment of around AUD350. Contact Leisa Donlan Email:
ldonlan@rotationalmoulding.com.
This is best price/performance quality tool available to the user of powder.
澳亚滚塑协会目前已在全球范围内提供这一新标准的干流漏斗，售价为350澳元。
这是为粉末使用者提供的最高性价比的测量工具。 22

23. New global standard for
Dry Flow Funnel fabrication 干流漏斗全球新标准
Surface roughness
of 16 micro inches
Material : Aluminium Alloy
Finish :Sulphuric Anodised
You can manufacture the
funnel yourself
23

24. Incoming Quality Control 质量控制
You don‟t have AUD350 (USD315) available within your Quality
Control budget?
You don‟t believe powder is going to cause any moulding
problems in your factory?
If you rely on a powder supplier for incoming raw material
Quality testing, request a copy of their testing certificate, for
each batch delivered.
Ensure that your powder suppliers are using the new global
standard funnel in their testing of powder quality.
您没有将350澳元（315美元）纳入您的质控预算?
您不相信粉末会在您的工厂生产中引起制模问题？
如果您依赖粉末供应商提供的原材料质量检测，务必要求他们提
供一份各批量检测认证副本。
确保您的粉末供应商在粉末质量测试中，使用了新的全球标准。 24

25. Example
of Incoming
Raw material
test certificate
原材料测试认证样本
25

26. 凡是能测量的，都能控制！
谢谢您
Contact details for information on sourcing dry flow funnel (and robust stand and density cup)
Email: ldonlan@rotationalmoulding.com
What Is Powder Grinding?
By Ian Hansen
26
ihansen@bushmans.com.au